Dr Ajithkumar D S
Dept. of Physiology & Biochemistry, GHMC, Calicut
Email : [email protected]
Human body is composed of about 60% water, 15% proteins, 15% lipids, 2% carbohydrates & 8% minerals.
Nucleus: DNA replication & transcription. Site of chromosomes.
Ribosome: site for protein synthesis.
Endoplasmic reticulum: Biosynthesis of proteins, glycoproteins, lipoproteins, drug metabolism (detoxification). Synthesis of cholesterol.
- Golgi body: Maturation of synthesized proteins.
- Lysosome: Degradation of proteins, carbohydrates, lipids & nucleotides. Lysosomes are the ‘suicide bags’, which contain many hydrolyzing enzymes.
- Mitochondria: ETC, TCA cycle, Beta oxidation of fatty acids, ketone body production, ATP generation etc…
- Mitochondria, the ‘Power house’ of the cell has its own DNA, can synthesis its own proteins. It is some time referred to as mini cell.
- Peroxisome: degradation of fatty acid & amino acid; production & degradation of H2O2.
- All cells in the body contain nucleus except mature erythrocytes.
- Transport mechanisms
- Active – requires energy; (40% of total energy)
i. Sodium, calcium pump;
ii. Uniport: carrying single solute.
iii. Symport: transporter carries 2 molecules in 1 direction.
iv. Aniport system: carrying 2 solutes in opposite direction.
i. Simple – occurs from higher 2 lower conc.:
ii. Facilitated – carrier mediated(glucose); ion channels(Na+, k+, cl–); ligand gated channels, voltage gated channels(nerve)
- Proteins are made by polymerization of amino acid through peptide bonds.
- Skeleton of peptide bond: N-C-C-N-C
- All amino acid are L ∞ – amino acid.
- Amino group attached to same carbon to which carboxy group is attached.
- Hydroxy amino acids: Serine, Threonine.
- Heterocyclic amino acid: Tryptophan & Histidine
- Sulphur containing amino acids: Cysteine & methionine.
- Imino acid: Proline
- Aromatic amino acid: Phenylalanine, Tyrosine.
- Amino acid with amide group: Asparagine & glutamine
- Branched chain amino acid: valine, leucine, isoleucine
- Classification based on metabolic fate:
- Purely Ketogenic: leucine
- Ketogenic & glucogenic: Lysine, Isoleucine, Phenyalanine, Tyrosine & Tryptophan.
- Glucogenic: remaining 14 amino acid
- Essential amino acid: Arginine, Histidine, Isoleucine, Leucine, Threonine, Lysine,Methionine, Phenyalanine, Tryptophan & Valine.
(Code to memorize: Any Help In Learning These Little Molecules Proves Truly Valuable).
- Semi essential amino acid: Arginine & Histidine
- Amino acid with its groups:
|Amino acid||Group present|
Properties of Amino acids
- Amino acid can exist as ampholytes or zwitterions (at iso-electric pH, amino acid will not carry net charge).
- Optical activity:
- Amino acid has an asymmetric carbon atom (4 different groups attached to carbon atom).
- Glycine is the simplest amino acid & has no asymmetric carbon atom.
- L-∞ amino acid occurs in nature.
- Primary structure of the protein refers to the basic sequence of covalent linked amino acids. Primary structure is not altered during denaturation. It determines biological activity of a protein.
- Secondary structure refers to the recurring arrangement along 1 dimension of the polypeptide chain. Hydrogen & electrostatic bond, hydrophobic interaction & vanderwaals force determines secondary structure.
- Tertiary structure refers to the manner in which polypeptide chains bend & fold in three dimensions to form globular proteins.
- Quartary structure refers to the configuration that develops when individual polypeptide chains group about each other to form a functional protein.
- The nitrogen content of ordinary proteins is 16% by weight.
- Proteins classified based on their composition & solubility:
- Simple protein: E.g. Albumin, globulins, protamines, prolamines, lectins, scleroproteins.
- Conjugated proteins: E.g. Glycoproteins, Lipoproteins, etc…
- Proteins classified based on their Shape:
- Globular protein: E.g. Albumin, globulins, protamines
- Fibrous proteins: E.g. collagen (abundant protein in animal tissue), elastin, keratin
- Proteins classified based on their functions:
- Catalytic proteins: E.g. enzymes
- Structural proteins: E.g. collagen, elastin, keratin (nail) etc…
- Contractile proteins: E.g. myosin, actin, flagellar protein.
- Transport proteins: E.g. Haemoglobin, myoglobin, albumin, transferrin.
- Regulatory proteins: E.g. ACTH, insulin, growth hormone
- Genetic proteins: E.g. Histones
- Protective proteins: E.g. immunoglobulins, interferons, clotting factors.
- Shape of proteins:
- Insulin: globular
- Albumin: oval
- Fibrinogen: elongated.
- Precipitation Reactions of proteins
- All proteins are least soluble at their iso-electric pH.
- Primary structure is not altered during the process of denaturation.
- Normal urinary protein excretion is 150mg.
- All enzymes are proteins & follow the physical and chemical
Classification of Enzymes:
- Oxidoreductases: Transfer of Hydrogen. e.g. Lactate dehydrogenase
- Transferase: Transfer of groups other than hydrogen. E.g. Aminotransferase.
- Hydolases: Cleave bond and add water. E.g. Trypsin.
- Lyases: Cleave without adding water. E.g. Aldolase.
- Isomerase: Intramolecular transfers. E.g. racemases & epimerases.
- Ligases: ATP dependent condensation of two molecules. E.g. Glutamine synthetase.
- The protein part of the enzyme is then named the Apo-enzyme, the prosthetic group (non protein) the Co-enzyme; & then these 2 portions combined together is called the Holo-enzyme.
- Co-enzyme is essential for the biological activity of the enzyme, acting by donating or accepting hydrogen or other groups like phosphate etc.
- Non-protein part of an enzyme(prosthetic group)
|Thiamine pyrophosphate(TPP)||Hydroxy ethyl|
|Pyridoxal phosphate(PLP)||Amino group|
|Tetra hydrofolate(FH4)||One carbon group|
- Metallo – enzymes: enzymes requiring certain metal ions for their action.
|1.||Xanthine oxidase; nitrate reductase||Mo|
|2.||Tyrosinase; phenolase; ascorbic acid oxidase||Cu|
|3.||Cytochrome enzymes; catalase; peroxidase; tryptophan oxidase; homogentiase||Fe|
|4.||Lecithinase A & C; lipases||Ca|
|5.||Carbonic anhydrase; lactic dehydrogenase; carboxy peptidase||Zn|
|6.||Peptidase; Phosphatases; ATP enzymes(hexokinases)||Mg|
|7.||Arginase; phosphogluco mutase; dipeptidases||Mn|
- That area of the enzyme where catalysis occurs is referred to as active site or active centre.
- Michalis-menten theory states that an enzyme (E) combines with a substrate (S) to form an enzyme-substrate (E-S) complex, which breaks down to give product (P).
Factors influencing enzyme activity
- Enzyme conc.: rate of a reaction is directly proportional of the enzyme conc.: when sufficient substrate is present.
- Substrate conc.: at half-maximal velocity is the Km value. It denotes that 50% of enzyme molecules are bound with substrate molecules at that particular substrate conc.:
- Substrate conc.: as substrate conc.: is increased, the velocity is also correspondingly increased in he initial phases; but he curve flattens afterwards.
- Product conc.: when product conc: is increased, the reaction is slowed, stopped or even reversed.
- Temperature: velocity of the reaction increases when temperature of the medium is increased.
- Enzyme has an optimum pH.
- Enzyme inhibition:
Competitive inhibition: here inhibitor molecules are competing with the normal substrate molecules for attaching with the active site of the enzyme.
Non-competitive inhibition (irreversible): there is no competition B/W substrate & inhibitor. The inhibitor usually binds to a different domain on the enzyme, other than the substrate binding site.
Non-competitive inhibition (reversible):
Uncompetitive inhibition: here inhibitor does not have any affinity for free enzyme. Inhibitor binds to enzyme-substrate complex; but not to the free enzyme.
Suicide inhibition: the substrate like compound initially binds with the enzyme & the first few steps of the pathway are catalysed. The new product irreversibly binds to the enzyme & inhibits further reactions.
Allosteric inhibition: enzyme activity may be regulated by either altering the activity of existing enzymes or by altering the conc: of enzymes.
- Iso-enzymes: Physically distinct forms of the same enzyme activity.
Normal values of important enzymes:
- Lactate dehydrogenase(LDH) in serum is 100 – 200 U/L.
- LDH1 predominates in myocardium(HHHH)
- LDH5 predominates in muscle (MMMM)
- Creatine kinase (CK) value is 15 – 100 U/L for males & 10 – 80 U/L in females.
- Aspartate amino transferase (AST or SGOT) is 8 – 20 U/L.
- Alanine amino transferase (ALT or SGPT) is 13 – 40U/L in male & 10 – 28U/L in females.
- Alkaline phosphate (ALP) is 40 – 125 U/L.
- Nucleotide phosphatase (NTP) is 2 – 10 IU /L.
- Gamma glutamyl transferase is 10 – 30 U/L.
- Acid phosphatase is 2.5 – 12 U/L.
- Prostate specific antigen is 1 – 5 mg/L.
- Cholinesterase is 8 – 18 U/ml.
- Glucose-6-phosphate dehydragenase is 125 – 250 U/ 1012 cells.
- Pancreatic Amylase is 50 – 120 IU/L.
- Lipase is 0.2 – 1.5 U/L.
- Aldolase is 1.5– 7 U/L.
- Carbohydrates are polyhdroxy aldehydes or ketones
- Carbohydrates are the main source of energy to body.
- General molecular formula of carbohydrates is Cn(H2O)n
- Classified into monosaccharide, disaccharides, oligosaccharides & polysaccharides.
- Molecules having only one actual or potential sugar group are called monosaccharides,which cannot be hydrolysed further.
- Polysaccharides having only one type of monosaccharide unit are calledhomopolysaccharides & those having different monosaccharide units areheteropolysaccharides.
- Glyceraldehyde is the reference molecule for carbohydrate.
- D sugars are naturally occurring sugars & body can metabolise only D sugars.
- Common monosaccharides
|carbon atom||Generic name||Aldoses||Ketoses|
Properties of carbohydrate
- Carbohydrates show streoisomer, optical activity, epimers & Anomerism.
- Stereoisomers: compounds having same structural formula but differ in spatial configuration.
- Epimerism: when sugars are different from one another, only the configuration with regard to a single carbon atom (other than the reference carbon atom).
Reactions of carbohydrate
- Osazone formation (Phenyl hydrazine): All reducing sugars form characteristic osazone crystals.
- Glucose & fructose form needle shaped crystals,
- Maltose form sun flower shaped crystals &
- Lactose form hedge-hog shaped crystals.
- Important disaccharides are sucrose, maltose, isomaltose & lactose.
- Sucrose is not a reducing sugar because it does not have free aldehyde or ketone group. (invert sugar).
- Isomaltose is a reducing sugar, contains 2 glucose units combined in ∞ – 1, 6 linkages.
- Salient features of important sugars
|Galactose||4th epimer of glucose|
|Mannose||2nd epimer of glucose|
|Glucose + galactose||Lactose (reducing)|
|Glucose + glucose||Maltose (reducing)|
|Glucose + Fructose||Sucrose(reducing) ∞ – 1, 2 glycosidic bond|
- Starch is the reserve carbohydrate of plant kingdom.
- Starch is made of unbranched part, amylaseformed of ∞ – 1, 4 glycosidic linkages & branched part, amylopectin made by ∞ – 1, 6 linkages.
- Amylopectin gives red colour to iodine reaction.
- Cellulose is a chief carbohydrate in plants. Due to the absence of enzyme cellubiase, man cannot digest cellulose.
- Inulin is a long chain homoglycan composed of D-fructose units with repeating beta-1, 2 linkages.
- Glycogen is the reserve carbohydrate of animal kingdom.
- Heteroglycans are polysaccharides containing more than one type of sugar residues.
- Heparin is the strongest acid in human body.
- Mucopolysaccharides or glycoaminoglycans (GAG) are carbohydrates containing uronic acid & amino sugars.
- When the carbohydrate chains are attached to a polypeptide chain it is calledproteoglycan.
- Lipids are heterogenous compounds related more by their physical rather than by chemical properties.
- Insoluble in water & soluble in non-polar solvents.
- Lipids are biomolecules of high energy values.
- Lipids provide fat soluble vitamins.
Classification of lipids:
a) Simple lipids: esters of fatty acids with glycerol or other higher alcohols.
- Triglyceride or fat
b) Compound lipids: fatty acid esterified with alcohol; but in addition they contain other groups.
- Phospholipids(fatty acid + alcohol(glycerol) + phosphoric acid)
- Nitrogen containing glycerophosphatides
- Non-Nitrogen containing glycerophosphatides
- Plasmalogens, containing long chain alcohol
- Phosphos sphingosides, containing sphingosine(long aliphatic amino alcohol)
- Lecithin(Phosphatidyl choline) (surfactant – diphosphatidyl choline)
- Cephalin (Phosphatidyl ethanol amine)
- Phosphatidyl serine
- Phosphatidyl inositol
- Phosphatidyl glycerol
- Diphosphatidyl glycerol (cardiolipin)
- Choline plasmalogen
- Ethanolamine plasmalogen
- Sphingomyelin(fatty acid + phosphoric acid + sphingosine + choline)
- Glycosphingolipids (carbohydrate + ceramide(sphingsine + fatty acid))
- Sulpholipids or sulfatides(carbohydrate + ceramide + sulfate)
- Sulphated cerebrosides (ceramide monohexosides)
- Sulphated globosides (ceramide oligosaccharides)
- Sulphated gangliosides.
c) Derived lipids: compounds derived from lipids or precursors of lipids.
d) Lipids complexed to other compounds: proteolipids & lipoproteins.
Classification of fatty acids
- Depending on total carbon atoms
- Even chain – most of naturally occurring fatty acids.
- Odd chain – microbial cell wall.
- Depending on length of hydrocarbon chain
- Short chain – 2 to 6 carbon atoms
- Medium chain – 8 to 14 atoms
- Long chain with 16 & above upto 24 carbon atoms.
- Depending on nature of hydrocarbon chain
- Saturated FA(containing no double bond):
- Eg: Acetic acid(C2); Butyric(C4); Palmitic(C16); Stearic(C18)
- Unsaturated FA (containing double bond):
- Eg-Oleic(C18); Linoleic(C18); Arachidonic(C20)
- Branched chain: Eg: Iso valeric acid(C5)
- Hydroxy FA: Eg: Cerebronic acid(C24)
- Saturated FA(containing no double bond):
- Saturated FA: have the general formula CH3-(CH2)n-COOH.
- Unsaturated FA: Properties are similar to saturated FA but also show properties due to double bond. Exhibit geometrical isomerism.
- All naturally occurring FA have the Cis configuration.
- Linoleic (C18 with 2 double bond), Linolenic acid (C18 with 3 double bond), Arachidonic acid(C20 with 4 double bond) & Clupanodonic acid (5 double bond) are polyunsaturated fatty acid (PUFA) are also called essential FA because they cannot be synthesized by the body.
- Hydrogenation produces saturation of double bond.
- Prostaglandinswith diverse physiological role confer them the status of local hormone.
- Mother’s milk contain 4% essential FA.
Properties of fatty acids
- Hydrogenation of oils can lead to solidification & saturation. Eg: Vanaspathi.
- Neutral fat, also called triglycerides are esters of trihydric alcohol, glycerol with FA.
- Oils are liquids at 20*C, mainly triglycerides of unsaturated FA from plant origin.
- Fats are solids at room temperature & contain mainly saturated FA of animal origin.
- Triglycerides are the storage form of lipids in the adipose tissue.
Properties of Triglycerides
- Saponification: Hydrolysis of triglycerides by alkali, the product is glycerol & soap.
- Saponification number:the No: mg of KOH required saponifying 1 gm of fat. (indication of molecular Wt of fat)
- Human fat: 194-198; butter 210-230; coconut oil 253-262.
- Iodine Number:the No: gm of iodine taken up by 100gm of fat. It is the index of degree of unsaturation.
- Butter 28; sunflower 130.
- Sphingomyelins are the only sphingolipid that contain phosphate & have no sugar moiety.
- Adipose tissue forms about 15% of body weight.
Various reaction included under metabolism.Glucose metabolism: Glycolysis; Cori’s cycle; Gluconeogenesis;
- Glycogen metabolism: Glycogenolysis; Glycogenesis; Glycogen storage diseases.
- Regulation of Blood sugar level: OGTT; Insulin; glycated Hb;
- Minor metabolic pathway of carbohydrates: HMP pathway; Fructose metabolism; Galactose metabolism;
- Metabolism of Fatty acids: FA oxidation; FA synthesis; Adipose tissue; Fatty liver & lipotropic factors; Ketone bodies; Cholesterol; Plasma lipids;
- Amino acid metabolism: Urea cycle; metabolism of amino acids;
- Citric acid cycle
- Electron transport chain
- Reaction takes place in cytosol.
- In this pathway glucose is converted to pyruvate (Aerobic condition) or lactate (Anaerobic), along with production of a small quantity of energy.
- 1 molecule of glucose produces 2 molecules of pyruvate.
- Only pathway taking place in all cells of the body.
- Preliminary step before complete oxidation.
- Provide carbon skeleton for synthesis of certain amino acid.
- Phophofructokinaseis the most important rate limiting enzyme of glycolysis pathway.
- ( Hexokinase & Pyruvate kinase are other important regulatory enzymes)
- Pyruvate dehydrogenase enzyme complex requires 5 cofactors for its activity: NAD, FAD, TPP, Lipoamide and CoA.
- Energy yield from glycolytic pathway: (Anaerobic condition) is 2 ATPS.
- Energy yield from glycolytic pathway: (Aerobic condition) is 8 ATPS.
- Energy yield per molecule of glucose when it is completely oxidized through glycosis plus citric acid cycle, under aerobic condition is 38ATPs.
Cori’s cycle or Lactic acid cycle:
- Reaction takes place in liver.
- Lactate formed from pyruvate by anaerobic pathway is sent to liver through blood, where it is oxidised back to pyruvate & taken by gluconeogensis pathway to produce glucose which enters blood & used again by muscle.
- It is the process by which new glucose is synthesized from non-carbohydrate precursors like lactate, glycerol & glucogenic amino acids.
- Pyruvate carboxylase; phosphoenol pyruvate-carboxy kinase; fructose-1,6-biphosphatase &glucose-6-phosphatase are the most important rate limiting enzyme of gluconeogenesis pathway.
- Energy requirement for gluconeogenesis: 6 ATPs are required to generate one glucose molecule.
- Free fatty acid & amino acid alanine released from muscle is the major substrate for gluconeogenesis.
- Glucagons & gluco corticoids increase gluconeogenesis, whereas insulin inhibits.
- The major metabolic significance of gluconeogenesis is maintenance of blood glucose under conditions of starvation.
- Glycogen is the storage form of carbohydrate in the human body.
- Glycogen content of liver(10gm / 100gm of tissue) is more than in the skeletal muscle ( 1- 2 gm / 100gm)
- Total quantity of muscle glycogen is more than liver glycogen because of the larger muscle mass.
- Major function of liver glycogen is to provide a source of glucose for maintenance of blood glucose level.
- Glycogen phosphorylase is the key enzyme in Glycogenolysis which removes glucose units one at time from the nonreducing end of the glycogen molecule.
- Glycogen phosphorylase attack ∞ -1, 4 glycosidic linkages.
- Debranching enzyme ∞ -1, 6 glucosidase can hydrolyse the remaining glucosyl unit at the branch point.
- The energy yield from one glucose residue derived from glycogen is 3 ATP molecules.
- The key enzyme for glycogen synthesis is glycogen synthase
- Branching enzyme: amylo 1, 4 – (1, 6 transglucosidase)
Regulation of blood sugar:
- Glucagon, Cortisol, Adrenaline & growth hormones are hyperglycemic, while Insulin is hypoglycemic.
- GTT is a well-standardised test, & is highly useful to diagnose DM in doubtful cases.
- Impaired glucose tolerance: here blood sugar values are above the normal level, but below the diabetic levels.
- Reducing substances in urine are both sugars & noncarbohydrate compounds.
|Galactose||Glucuronides of drugs|
- Specific tests for sugars:
- Insulin is a protein hormone with 2 polypeptide chains; A chain with 21 amino acids & B chain with 30 amino acids are joined by a pair of disulphide bonds.
- Glycated Hb
- The best index of long term control blood glucose level.
- HbA1 C reveals the mean glucose level over the previous 8 to 10 weeks. (also 120 days).
- Normal value: 4 – 8%.
Hexose monophosphate shunt (HMP) or Pentose phosphate pathway:
- Take place in cytoplasm.
- An alternate pathway for glucose metabolism.
- Major purpose of this pathway is to generation of NADPH & ribose for biosynthetic reactions.
- First reaction i.e. formation of 6-phopho glucono lactate from glucose-6-phosphate in the presence of glucose-6-phosphate dehydragenase is the rate limiting step.
- Totally 2 NADPH is formed & 1 pentose phosphate with liberation of CO2.
- Significance of NADPH:
- Needed for biosynthetic reaction of fatty acid & cholesterol.
- Formation of glutathione (required for maintaining RBC integrity).
- Prevent formation of Met-haemoglobin.
- Preserving transparency of lens.
Glucoronic acid pathway of glucose:
- Important as it provide UDP-glucoronic acid.
- UDP-glucoronic acid is needed for conjugation of bilirubin & synthesis of glycoaminoglycans & drugs.
- Metabolized mainly in liver & free fructose is seen in large quantities in seminal plasma.
- Sorbitol pathway synthesis of fructose from glucose.
Fatty acid metabolism:
- Long chain fatty acids are absorbed by forming micelles with the help of bile salts.
- Serum appears milky after a high fat meal due to presence of chylomicrons.
- Daily excretion of fat in faeces is 5g.
- When daily excretion of fat in faeces is more than 6g / day, it is called steotorrhea.
Beta-oxidation of fatty acid:
- Takes place only in even chain fatty acids only & called beta-oxidation because oxidation takes place in beta carbon atom of fatty acid.
- Activation takes place in cytoplasm but beta-oxidation in mitochondria.
- Carnitine is involved in transfer of fatty acid.
- Energy yield from beta-oxidation of palmitic acid (16C) = 129 ATP.
- Energy yield from beta-oxidation of stearic acid (18C) = 147 ATP.
Oxidation of odd chain fatty acid:
- Fatty acid is oxidized exactly in same manner; at the end 3 carbon unit propionyl CoA is produced.
Synthesis of fatty acid:
- Pathway occurs in cytoplasm.
- The 1st step in the fatty acid synthesis is the carboxylation of acetyl CoA to form malonyl CoA. Enzyme: Acetyl CoA carboxylase.
- Acetyl CoA carboxylase is the rate limiting enzyme.
Synthesis of triglycerides (TAG):
- TAG synthesis in adipose tissue is for storage of energy whereas in liver it is mainly secreted as VLDL & is transported.
- Fatty liver refers to deposition of excess triglycerides in the liver cells.
- Lipotropic factors: required for the normal mobilization of fat from liver, which afford protection against development of fatty liver.
- Choline, Lecithin & Methionine are lipotropic factors. (Vit E, selenium & Betaine).
- Ketone bodies:
- Primary ketone bodies: Aceto acetate(Diabetic ketoacidosis)
- Secondary ketone bodies: acetone & beta hydroxyl butyrate.
- Presence can be detected by Rothera’s test.
- Cyclopentano per hydro phenanthrene ring forms the skeleton for cholesterol.
- Best source of cholesterol is egg yolk.
- Average diet contains about 300mg of cholesterol / day.
- Body synthesis 700mg cholesterol / day.
- Cholesterol excreted through bile is 500mg.
Synthesis of Cholesterol:
- Liver is the major site.
- Location: partly in endoplasmic reticulum & partly ion cytoplasm.
- HMG CoA reductase is the regulatory enzyme in synthesis of cholesterol.
- Chylomicron: transport TAG from gut to muscle & adipose tissue.
- VLDL: Transport TAG from liver to muscle.
- LDL: Transport cholesterol from liver to heart.
- HDL: Transport cholesterol from heart to liver.
- Lipoprotein with max. of TAG is chylomicrons. (88%)
- Lipoprotein with max. of phospholipids is HDL.
- Lipoprotein with max. of free cholesterol is HDL2
- LDL above 160 mg / dl carries definite risk of atherosclerosis.
- HDL above 60 mg / dl are desirable & said to be protective against atherosclerosis.
Amino acid metabolism
- Protein has no storage form in human body.
- Daily protein load for digestion is about 100 – 200 mg.
- Protein enzymes are secreted as inactive zymogens which are converted to active form in intestinal lumen.
- Rennin is active in infants & is involved in curdling of milk.
- (Renin is proteolytic enzyme, secreted by kidneys).
- Pepsin is the protelytic enzyme secreted by chief cells of stomach.
- Optimum pH for pepsin is 2.
- Optimum pH for pancreatic enzyme is 8.
- Pancreatic juice contains endopeptidase: trypsin, chymotrypsin & elastase.
- Once activated, trypsin will activate other enzyme.
- Final hydrolysis of proteins are done by carboxy peptidases A & B into dipeptides & tripeptides.
- The major source of ammonia is from the catabolism of amino acids (minor – from purine & pyrimidine metabolism).
- Ammonia formed is removed as urea through urine.
- Glutamic acid is the transport form of ammonia. (in brain: glutamine).
- Urea is the end product of protein metabolism.
- Exclusively in liver that too in cytoplasm.
- Carbamoyl phosphate formed from ammonia, Co2 & H2O in the presence of carbamoyl phosphate synthetase – I is the rate limiting step in urea cycle.
- Urinary excretion is 15 to 30 g / day. (80% of urinary organic solids).
One – carbon metabolism:
- One carbon (1C) groups play a pivotal role in donating carbon atoms for synthesis of different types of compounds.
- Eg: formyl – CHO; formimino –CH=NH; methenyl = CH; methylene –CH2; metheny.
- One –carbon groups, except methyl group, are carried by tetra hydro folic acid (THFA).
Individual Amino acid metabolism
Glycine: (simplest amino acid; glucogenic)
- Metabolic importance:
- Biosynthesis of Heme, Creatine; Purine; Glutathione;
- For conjugating with bile acid.
Serine: (Aliphatic hydroxyl amino acid)
- Metabolic importance:
- Biosynthesis of phospholipids, Choline(Acetyl choline)
- Formation of Cysteine.
- Donate for one-carbon group.
Alanine: (Non essential; glucogenic)
- Metabolic importance:
- Formation of (ALT) alanine amino transferase.
- Alanine is quantitatively the most important amino acid taken up by the liver from peripheral.
Methionine: (Essential; glucogenic)
- Metabolic importance:
- Amino acid containing sulphur.
- Methionine is activated to ‘Active methionine’ or S-adenosyl methionine (SAM).
Cysteine: (Non essential; glucogenic)
- Metabolic importance:
- Formation of Glutathione (Gamma glutamyl cysteinyl glycine) along with glutamic acid & Glycine.
- Formation of active sulfate (PAPS – phosphor adenosine phosphor – 5’-sulfate)
- Homocystinuria: elevated level of homocysteine & homocystine in serum & urine.
(Cyanide – nitroprusside test).
Glutamic acid: (Glucogenic)
- Transamination reaction.
- Intermediate in kreb cycle.
- Formation of GABA.
- Formation of Glutathione (Gamma glutamyl cysteinyl glycine).
Aspartic acid: (Glucogenic)
- Important for synthesis of purines & pyrimidinies.
- Intermediate in Urea cycle.
Lysine: (Essential; Ketogenic)
- Deficient in cereals.
- Only Amino acid which does not under go transamination.
- Precursor of Carnitine.
Arginine: (Semi-essential: Glucogenic; contains guanidium group)
- Formed in urea cycle.
- Precursor of nitric oxide & Creatine.
Branched chain amino acids: (Valine, Leucine & Iso-leucine)
- All 3 are essential amino acids, valine-glucogenic; leucine-ketogenic & isoleucine-both)
- Important fuel for brain during starvation.
- Maple syrup urine disease: basic biochemical defect is deficient decarboxylation of branched chain ketoacids.
Phenyl alanine & Tyrosine: (Essential; partly gluco-ketogenic)
- Aromatic amino acid.
- Needed for the synthesis of Melanin, DOPA (dihydroxy phenyl alanine), Dopamine, and Epinephrine & Nor-epinephrine.
- Synthesis of thyroid hormones.
- Phenyl ketonuria: resulting from the deficiency of Phenyl alanine hydroxylase. Characterized by mousy odour of urine.
- Alkaptonuria: from the deficiency of homogenisate oxidase. Characterized by blackening of urine on standing.
- Albinism: resulting from deficiency of tyrosinase; due to defective synthesis of melanin.
Tryptophan: (Essential; Aromatic amino acid. Both gluco & ketogenic)
- Characterized by presence of indole ring.
- Necessary for the synthesis of nicotinic acid (NAD).
- 60 mg of tryptophan will be equivalent to 1 mg of nicotinic acid.
- Needed for the synthesis of serotonin (5-hydroxy tryptoamine) & melatonin (hormone of pineal gland).
- Hartnup’s disease: Amino acid absorbtion is defective.
- Characterized by presence of imidazole ring.
- Needed for the formation of FIGLU & Histamine.
- Acting as a buffer in much reaction.
- Rate limiting steps:
|Cholesterol synthesis||HMG CoA reductase.|
|Bile acid synthesis||7 – alpha hydroxylase.|
|Fatty acids synthesis||Acetyl CoA carboxylase|
|Porphyrin synthesis||Amino levulinic acid synthetase|
|Uric acid synthesis||Xanthine oxidase|
|Purine bio synthesis||PPRP synthetase|
- Sites of Bio chemical reaction:
|3.||Oxidative decarboxylation of pyruvate||Mitochondria|
|5.||Gluconeogenesis||Mitochondria & cytosol.|
|7.||Urea synthesis||Mitochondria(reaction 1 & 2)Cytosol (reaction 3, 4 & 5)|
|8.||ETC||Inner mitochondrial membrane.|
- Identification tests:
|1||Murexide test; Schiff’s test||Uric acid|
|2||Rothera’s test; gerhardt’s test||Acetone(ketone bodies)|
|7||Vanden-bergh reaction||Serum bilirubin|
|8||Sanger’s method||N-terminal amino acid|
|9||Edman method||N-terminal amino acid|
|10||Addis count||Urinary sediment count|
|11||Winslow test||Amylase (serum or urinary)|
|12||Sulkowitch test||Urinary calcium|
|13||Benedict’s test||Urinary sugar(reducing)|
|14||Jaffe’s test; weyl-salkowski’s||Creatinine|
|15||Hypo bromide test||Urea|
|18||Guthrie’s test||Phenyl ketonuria|
|23||Biuret Reaction||Peptide Bonds|
|24||Ninhydrin reaction||Amino acids|
|25||Xanthoproteic||Amino acid with benzene ring|
|28||Pauly’s||Histidine & Tyrosine|
- Inborn errors of metabolism:
|1.||Von gierke’s disorder||Glucose-6-phosphate|
|3.||Cori’s or forbes disorder||Debranching enzyme|
|4.||Anderson amylopectinosis||Branching enzyme|
|5.||McArdle’s disorder||Muscle phosphorylase|
|6.||Her’s disease||Liver phosphorylase|
|7.||Phenyl ketonuria||Phenyl alanine hydroxylase|
|8.||Alkaptonuria||Homogentisic acid oxidase|
|10.||Oast house disease||Methionine malabsorbtion|
|11.||Maple syrup disease||Decarboxylation of branched chain ketoacids|
|15.||Tay sach’s||Hexosaminidase A|
Citric acid cycle or kreb’s cycle or TCA cycle
- Absent in mature RBC.
- Final oxidative pathway that oxidases acetyl CoA to CO2.
- Source of reduced Co-enzymes (FADH2 & NADH) that provide the substrate for respiratory chain.
- Link between catabolic & anabolic pathway.
- Forms precursors for synthesis of amino acid & nucleotides.
- Components have direct or indirect effect on other pathways.
- Location: mitochondria.
- Various substrates are citrate, aconitase, isocitrate, oxalo acetate, alpha keto glutarate, succinyl CoA, succinate, fumarate, malate & oxalo acetate.
- The cycle is tightly coupled to respiratory chain providing ATP.
- 12 ATP are produced during each cycle.
- Kreb’s cycle is the largest generator of ATP among metabolic pathway.
Metabolic profile of Organs:
- Brain represents 2% of body weight, it needs 20% of cardiac output.
- No stored fuel in brain.
- Blood glucose level below 30 mg/dl is fatal.
- 75% of total glycogen is stored in skeletal muscle.
- Brain, retina & embryonic tissue utilize glucose as sole source of energy.
Major fuel in different organ:
|Brain||Skeletal muscle||Cardiac muscle||Adipose tissue|
|After a meal||Glucose||Glucose &Fatty acid||Glucose &Pyruvate||Fatty acid &Glucose|
|Fasting||GlucoseKetone bodies||Ketone bodies &Branched chain amino acid||Ketone bodies||Fatty acid &Ketone bodies|
Primary metabolism: digestion in GIT converts the macromolecules into small units. Eg: proteins into amino acids.
Secondary or intermediatory metabolism: reducing equivalents are generated in mitochondria through TCA.
Tertiary metabolism of internal respiration or cellular respiration: reduced equivalents enter into ETC, where energy is released.
- Transfer of electrons from the reduced Co-enzymes through the respiratory chain to oxygen is known as biological oxidation.
- Energy released during the process is trapped as ATP.
- This coupling of oxidation with phophorylation is called oxidative phosphorylation.
- ATP is the universal currency of energy with in the living cells.
Electron transport chain:
- The electrons flow from the more electronegative components to more electro-positive components.
- All the components of ETC are located in the inner membrane of mitochondria.
- There are 4 distinct multi-protein complexes, named complex – I, II, III & IV.
- These are connected by 2 mobile carriers Co-enzyme Q & cytochrome C.
- FADH2 produces only 2 ATP molecules & NADH produce 3 ATP.
ETC Complex – I (NADH-CoQ reductase or NADH dehydrogenase complex)
- It is an aggregation of 25 different proteins.
- It contains FMN & iron – sulphur protein (Fe-S)
- NADH is the donor of electrons.
- FMN accepts them & get reduced to FMNH2, and then it is transferred to Fe-S.
- Finally the electrons are transferred to Co-enzyme Q (Ubiquinone).
- Over all function of this complex is to collect the pair of electrons from NADH & pass them to CoQ.
- Energy release is 12Kcal/mol.
- One ATP molecule is generated.
ETC Complex – II (Succinate-Q-reductase):
- Electrons from FADH2 enter the ETC at the level of Co-enzyme Q.
- This step does not liberate enough energy.
ETC Complex – III (Cytochrome reductase):
- Multi protein complex.
- Consist of Fe-S, cytochrome b & cytochrome C1.
- Free energy is -10 Kcal/mol.
- 1 ATP is formed.
ETC Complex – IV (Cytochrome oxidase):
- Contain different proteins, including cytochrome a & cytochrome a3.
- Free energy is 24 Kcal/mol.
- 1 ATP molecule is synthesized.
- Defibrinated plasma is called serum which lacks coagulation factors including prothrombin & fibrinogen.
- Liver produce about 12 g albumin / day.
- Carrier protein or transport protein of plasma.
Compound bound or transport
|1.||Albumin||3.5 – 5 g / dl||Bilirubin, Ca+, thyroxine|
|Pre-albumin(Trans thyrectin)||25 – 30 mg / dl||Steroid hormones|
|Retinol binding protein||3 – 6 mg / dl||Retinol (Vit A)|
|Thyroid binding globulin (TBG)||1- 2 mg / dl||Thyroxine|
|TranscortinCortisol binding globulin (CBG)||3 – 3.5 mg /dl||Cortisol|
|Haptoglobin||40 – 175 mg / dl||Hb|
|Transferrin||200 – 300 mg / dl||Iron|
|Hemopexin||50 – 100 mg / dl||Free heme|
|HDL||30 – 60 mg / dl||Cholesterol|
|LDL||80 – 175 mg / dl||Cholesterol, phospholipids & TAG|
- Enzyme which helps in incorporation of iron into transferritin (contains 6 to 8 copper atoms).
- Normal value 25 – 50 mg / dl.
- Decreased in Wilson’s hepatolenticular degeneration.
- T – Lymphocytes are the effectors cells for cell – mediated immunity.
- B- Cells govern humoral immunity.
- Immuno globulin G (IgG):
- Constitutes about 70 – 80 % of total immunity.
- Major antibody of secondary immune response.
- Only IgG can cross placenta & is the major protective antibody in newborns.
- Immuno globulin M (IgM):
- Predominant class of antibodies in primary response.
- Immuno globulin A (IgA):
- Secretory antibodies present over mucus membrane.
- Immuno globulin E (IgE):
- Cytophilic antibodies & mediate allergy.
- Hypersensitivity & anaphylaxis.
- Major structural protein found in connective tissue is collagen.
- 25 – 30 % of total weight of protein in body is collagen.
- Elastin: protein found in connective tissues. Eg: ligaments, walls of blood vessels.
- Fibronectin: cell – surface protein.
- Laminin: basement membrane protein.
- Keratin: in hair, skin, nails, horn.
- Contractile protein: Actin, Myosin, Tropomyosin & Troponin.
- Cytoskeleton: Spectrin, Calmodulin, Micro filaments, microtubules.
- Lens protein: Crystallins.
- Hb is a conjugated protein having heme as prosthetic group & protein, the globin.
- Globin polypeptide has 2 alpha & 2 beta.
- Each gram of Hb contains 3.4 mg of iron.
- In Hb iron remains in ferrous state.
- Heme is a derivative of porphyrin.
- Porphyins are cyclic compounds formed by fusion of 4 pyrrole rings.
- Formation of delta amino levulinic acid from glycine & succinyl CoA in the presence of ALA – synthase is the rate limiting step in heme synthesis.
- Heme synthesis takes place in mitochondria.
- Catabolism of heme results in the formation of bilirubin.
- Primary bile acids: Glycocholic acid, glycochenodeoxycholic acid, taurocholic acid, taurocheno-deoxy cholic acid.
- Secondary bile acids: deoxy cholic & lithocholic acid.
- Bile acids are synthesized exclusively in liver.
- Types of Hb:
- Hb A: 2 alpha & 2 beta chains
- Hb F: 2 alpha & 2 gama chains (have more affinity for O2 than adults.
- Adult blood contains 97% Hb A, 2 % Hb A2 & 1 % Hb F.
- Respiratory quotient (RQ): defined as the ratio of volume of CO2 produced to O2 consumed.
- RQ: carbohydrate – 1; Fat – 0.7; Protein – 0.8.
- BMR: adult men = 34 – 37 Kcal / sq mt / hour.
- BMR: adult men = 2000 Kcal.
- BMR is low in newborn, old age, females & large individuals.
- Carbohydrates may provide 60 – 65 % of total calories.
- Dietary fibre requirement is about 30g / day.
- Ideal fat intake is about 15 – 20 % may be PUFA.
- Cholesterol content of egg yolk – 1300 mg / 100gm. Brain – 2000 mg / 100gm.
- Biological value of proteins: Egg – 90; Milk – 84; Meat – 80.
- Balanced diet should contain carbohydrate, protein & fat in the ratio 60: 20: 20.
- Recommended daily allowance of proteins: Adults – 1g/kg; Pregnancy – 2 g/kg; Lactation – 2.5g/kg
- The total energy expenditure for protein synthesis per day is 15% of basal metabolism in humans.
Acid – base balance:
- pH of plasma is 7.4.
- Acidosis is pH below 7.38; Alkalosis is pH more than 7.42.
- Death occurs when pH is above 7.6.
- Normal bicarbonate level of plasma varies from 22 – 26 mmol/litre.
- Normal carbonic acid conc.: in blood is 1.2 mmol/litre.
- Composition of nucleotides include:
- Nitrogenous base
- Pentose sugar (ribose or deoxy ribose)
- Phosphate group esterified with sugar.
- Purine bases: same in both DNA & RNA.
- Adenine & guanine
- Minor purines are hypoxanthine, xanthine & uric acid.
- Biosynthesis of purine occurs in cytoplasm of liver.
- Phopho-ribosyl amido transferase is the rate limiting enzyme in the synthesis of purine.
- End product of purine catabolism is uric acid.
- Pyrimidine bases:
- Cytosine (both DNA & RNA)
- Thymine (DNA)
- Uracil (RNA)
- Carbamoyl phosphate synthetase is the rate limiting enzyme of pyrimidine synthesis.
- DNA structure is formed by units combined through 3’ – 5’ phospho diester bonds.
- Chargaff’s rule states that base pairing should be A=T & C=G.
- Length of DNA in a single cell is 1.74 meters.
- Southern blot analysis: DNA finger print
- Western blot analysis: AIDS
- Northern blot analysis: to detect RNA
- Fat soluble vitamin doesn’t have Co-enzyme activity.
- Vitamin with cholesterol lowering property – Niacin.
- Vit K dependent clotting factor II, VII, IX & X.
- Nature’s most potent anti-oxidant is Vit E.
- Vitamins with anti-cancer activity are Vit A & Vit E.
- Vitamin with anti-infective activity is Vit A.
- Vitamin stored in adipose tissue is Vit E.
- Vitamin B12 is absorbed from terminal ileum.
- Water soluble vitamins which are stored in the body are Vit B12 & Vit C.
- Vitamin D is a hormone & not a vitamin.
- Co-enzyme form of Vit B complex:
|Vitamin||Co-enzyme form||Enzyme with which acting|
|Niacin||Nicotinamide adenine di nucleotide (NAD)Nicotinamide adenine dinucleotide phosphate (NADP)||Dehydrogenases|
|Riboflavin||Flavin mono nucleotide (FMN)Flavin adenine di nucleotide (FAD)||Dehydrogenases|
|Lipoic acid||Lipoic acid||Pyruvic acid Dehydrogenase|
|Panthothenic acid||Co-enzyme A||Thiokinase|
|Thiamine||Thiamine pyrophosphate (TPP)||Oxidative decarboxylationTransketolase|
|Folic acid / cyanocobalamine||Tetra hydro folic acid (THF)|
|Calcium||500 mg /day||9 – 11 mg dl|
|Phosphorus||500 mg /day||3 – 4 mg / dl|
|Magnesium||400 mg /day||1.8 – 2.2 mg / dl|
|Sodium||5 – 10 g||Plasma 136 – 145 mEq/L|
|Potassium||3 – 4 g / day||Plasma 3.5 – 5 mEq/L|
|Chloride||5 – 8 g / day||Plasma 96 – 106 mEq/L|
|Iron||20 mg||100 – 150 µg/dl|
|Copper||1.5 – 3 mg / day||75 – 175 mg/dl|
|Iodine||150 – 200 µg / dl||5 – 10 µg / dl|
|Manganese||5 – 6 mg / day||8µg%|
|Zinc||15 mg / day||100 mg / dl|
|Molybdenum||75 – 200 µg / day|
|Nickel||500 µg||0.1 – 1 µg / dl|
|Chromium||50 – 75 µg||25 nanogram / dl|
|Selenium||50 – 100 µg||50 – 100 µg|
Concentration of constituents in serum:
|Total protein||6.2 – 8.2 gm%|
|Albumin||3.5 – 5 g/dl|
|Globulins||2.5 – 3.5 g/dl|
|Protein bond iodine||4 – 8 µg%|
|Ceruloplasmin||25 – 50 mg/dl|
|Alpha feto protein(AFP)||5 – 15 ng/ml|
|Calcium||9 – 11 mg/dl|
|Phosphorus||6 – 18 mg/dl|
|Magnesium||1.3 – 2.5 mEq/L|
|Total sulphates||1.2 mg/dl|
|Bicarbonate||22 – 26 mEq/L|
|Sodium||136 – 145 mmol/L|
|Potassium||3.5 – 5 mmol/L|
|Chloride||96 – 106 mmol/L|
|Copper||75 – 175 mg/dl|
|Iron||100 – 150 µg/dl|
|Cholesterol||150 – 200 mg/dl|
|HDL(male)HDL(female)||30 – 60 mg/dl35 – 75 mg/dl|
|LDL||80 – 175 mg/dl|
|Triglycerides MaleFemale||50 – 200 mg/dl40 – 150 mg/dl|
|Phospholipids||150 – 200 mg/dl|
|Free fatty acid||10 – 20 mg / dl|
|Bilirubin (Total)||0.2 – 1.0 mg/dl|
|Creatinine||0.7 – 1.4 mg/dl|
|Creatine||0.2 – 0.4 mg/dl|
|Osmolality||278 – 305 m osmol / g|
|Urea||20 – 40 mg/dl|
|Uric acid||3.5 – 7 mg/dl|
|T3||120 – 190ng/dl|
|T4||5 – 12 µg/dl|
|TSH||0.5 – 5 µU/dl|
|Vit A||25 – 70 µg%|
|Vit B2 (Riboflavin)||22 – 44 µg%|
|Folic acid||5 – 20 µg%|
|Vit C||135 – 800 µg%|
|17 – hydroxycorticoids||8 – 18 µg%|
|Cortisol||6 – 25 µg%|
|ACTH||0.5 m units%|
|IgG||800 – 1530 mgm%|
|IgA||50 – 200 mgm%|
|IgM||40 – 120 mgm%|
- Normal urine analysis:
|Normal urine analysis|
|Total 24 hours volume||1.5 litres (average)|
|Colour||Straw or yellowish|
|Reaction||Acidic (average pH 6.0)|
|Specific gravity||1.010 – 1.025|
|Crystals||May or may not be present|
- Concentration of constituents in Urine:
|Potassium as KO2||3 gm|
|Urea||20 – 30 gm|
|Uric acid||0.7 – 1 gm|
|Ammonia||0.6 – 0.7 gm|
|Hippuric acid||0.6 gm|
|17 – ketosteroids||6 – 18 mgm / 24 hrs urine|
Composition of faeces:
|Inorganic ashes||15 %|
|Ether soluble substances||15 %|
|Nitrogenous part||5 %|
|Total fat||Upto 25 % of dried faeces|
|Split fat||More than 75 % of faecal fat|
- Composition of C.S.F:
|Total volume||100 – 110 ml|
|Specific gravity||1.004 – 1.006|
|Pressure||100 – 110 mm 0f water|
|Cell count||0 – 3 / cmm|
|Potassium||10 – 12 mgm %|
|Chloride||700 mgm %|
|Bicarbonates||40 – 60 mgm %|
|Phosphate||1.8 mgm %|
|Sulphate||0.6 mgm %|
|Glucose||50 – 70 mgm %|
|Proteins||20 – 40 mgm %|
|Cholesterol||0.06 – 0.2 mgm %|
|Urea||10 – 30 mgm %|
- Composition of Semen:
|Amount||2 – 6 ml|
|Consistency||Viscid on ejaculation|
|Liquefaction||8 – 10 minutes|
|Fructose||0.04 – 4 %|
|Citric acid||0.1 – 1 %|
|Ascorbic acid||0.01 %|
|MotilityActive motileSluggish motileNon motile||80 – 90 %5 – 10 %5 – 10 %|
|Abnormal forms||Not more than 10 %|
|Total count||More than 80 million / c.c|
|Normal count varies||100 – 200 million / c.c|
- Composition of Lymph:
|Proteins||2 – 4.5 gm %|
|Fat||Lower during fasting,Increase 5 – 15 % after meals|
|Sugar||130 mgm %|
|Urea||20 – 25 mgm %|
|Non protein nitrogen||34 mgm %|
|Creatine||1.5 mgm %|
|Chlorides||700 mgm %|
|Calcium||9 – 10 mgm %|
|Inorganic phosphates||5.5 mgm %|
|Vit A (retinoid)||Normal vision – present in photo pigment.|
Growth & differentiation of tissues.
Reproductive systemNight blindness
Follicular hyperkeratosisAnimal source: milk & its product, fish liver oil, egg yolk & liver. Vegetable source: carrot, papaya, mango, green leafy veg.Adult: 750 µg
Children: 400 – 600 µg
Pregnancy: 1000 µg
Lactation: 1200 µgVit D (Cholecalciferol)Absorption of calcium & phosphorus from intestine & renal tubules. Mineralization of bone.Rickets – children.
Osteomalacia – adult.Exposure to sunlight
Fish liver oil, egg yolk, milk.Adult: 5 µg
Children : 10 µg
Pregnancy: 1200 µg
Lactation : 1200 µgVit E (Tocopherol)Nature’s most powerful anti-oxidant. Boost immune response. Reduce the risk of myocardial injury. Anti –infertility vitamin.Not been reported but study has showed that it may cause fragility of RBC.Vegetable oils. Eg. Wheat, sunflower, safflower, cotton seed & palm oils.Adult: 10 mg
Children : 8 mg
Pregnancy: 10 mg
Lactation : 12 mgVit K naphthoquinone derivativeNecessary for coagulation. Functional activity of C-reactive protein.Heamorrhagic disease esp. in children.
Prothrombin & clotting time is delayed.Green leafy vegetables.50 – 100 mg / dayVit C
(Ascorbic acid)Protein metabolism of praline, lysine, tryptophan & tyrosin. Iron & folic acid metabolism. Anti-oxidant property.Scury, haemorragic tendency.Amla (Indian gooseberry), guava, lime, lemon & green leafy vegetables.75 mg / dayVit B1
(Thiamine)Co-enzyme form is thiamine pyrophosphate (TPP). Carbohydrate metabolism.Beri beri , polyneuritisCereals (food grains)Adult: 1 – 1.5 mgVit B2Co-enzyme form is FAD & FMNGlossitis, cheilosis & angular stomatitisLiver, dried yeast, egg, milk, fish, whole cereals, legumes & green leafy vegetables.Adult: 1.5 mg
Pregnancy / Lactation: 1.7 – 2 mgNiacinCo-enzyme form is NAD & NADPPellagra: diarrhea, Dementia & Dermatitis.Dried yeast, rice polishing, liver, peanut, whole cereals, legumes, meat & fish.Adult: 20 mg
Pregnancy: 22 mg
Lactation : 25 mgVit B6 (Pyridoxine)Co-enzyme form is pyridoxial phosphate (PLP), protein metabolism.Neurological symptoms, dermatological symptoms & haematological manifestationDried yeast, rice polishing, liver, peanut, whole cereals, legumes, meat & fish.Adult: 2 mg
Pregnancy: 2.5 mgPantothenic acidCo-enzyme form is
Co-enzyme A, fat metabolismBurning foot syndrome,Yeast, liver & eggs are good source.10 mg / dayFolic acidTetrahydro folic acid (THFA) is the co-enzyme form which is known as a carrier of one carbon groups.Megaloblastic anemia, hyper-homocysteinemia, neural tube defect in fetus.Yeast, green leafy vegetables.Adult: 100 µg
Pregnancy: 300 µg
Lactation: 150 µgVit B12
(Cyanocobalamin)Metabolism of odd chain fatty acid. Homocysteine metabolism.Addisonian pernicious anemia, all manifestation of folate. demyelinationNot present in vegetables. Liver is the richest source. Meat, fish, egg.Adult: 1 µg
Pregnancy / Lactation: 1.5 µgBiotin
(Anti egg white injury factor)Needed for carboxylation reactionsDermatitis, atrophic glossitis, hyperesthesia, muscle pain.Normal bacterial flora.200 – 300 µg
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