Introduction, Classification of Vitamins, Fat –Soluble Vitamins-) Vitamin A ,Biochemical Function of Vitamin A, Deficiency of Vitamin A, Vitamin D ,Vitamin E, Deficiency and Role of Vit.E , Vitamin K, Water-Soluble Vitamins, Thiamine, ) Riboflavin , Nicotinic Acid, Pantothenic acid , Pyridoxine , Biotin, Deficiency of folic acid, Cyanocobalamin, structure and deficiency of co-enzyme B12 , Lipoic acid, Non B-Complex, Ascorbic acid , benifites of vit. C, CO-ENZYMES,
3. Introduction
◦ All living organisms require vitamins.
◦ Vitamins are a group of organic nutrients required in small
quantities for different biochemical functions
◦ Generally cannot be synthesized in body and must supplied
through diet.
◦ They also called as growth factors.
5. 1. Fat –Soluble Vitamins
A) Vitamin A (Retinol)
In plants, Vit. A is found in the form of provitamin A.
All provitamin A compounds belong to family pigmented hydrocarbons are
called carotenoids.
Vit. A found in animal live tissue.
Fish liver oil also contain Vit. A abundantly.
Retinol, retinal and retinoic acid are termed as vitamers of vitamin A.
6. ◦ Retinols present in animal tissue as retinyl ester with long chain fatty acids.
◦ This is an aldehyde obtained by the oxidation of retinol.
◦ Retinal and retinol are interconvertible.
7. Biochemical Function of Vitamin A
◦ Normal function of retina.
◦ Vitamin A is needed for the formation of rhodopsin.
◦ It is light receptor protein present in the retina.
Opsin (protein) + Chromophore (11 cis retinal) Rhodopsin
o Light energy is converted into chemical energy and finally performs a
biological sense.
o Antioxidant activity.
8. ◦ Growth and differentiation of epithelial tissues.
◦ Bone growth.
◦ Gene transcription.
◦ Immune function.
9. Deficiency of Vitamin A
1) Night blindness ( nyctalopia)
2) Vit.A deficiency may lead to abnormalities in tooth formation refelected in
defective enamel.
3) Vit. A deficiency leads to histological change in taste buds and surrounding
tissues resulting in the taste perception.
4) It may diminished production of corticosteroids, growth failure and
retardation.
5) In vit. A deficiency increases the respiratory tract infection due to decreased
mucous secretion .
11. B) Vitamin D
It required for the formation of bones.
It regulates the absorption and utilization of calcium & phosphorous..
Ergocalciferol ( Vit. D2) & Cholecalciferol (Vit. D3) are precursors of active
form of Vit. D.
Ergosterol is converted into ergocalciferol (Vit. D2) in the plants by the
action of sunlight.
Vitamin D deficiency results in rickets.
12. ◦ In 1921, Mellanby recognised that cod-liver oil contains a factor that prevent
rickets.
13. C) Vitamin E (alpha-tocopherol)
It is also known as anti-sterility vitamin.
The richest sources of Vit. E are vegetable oils and wheat germ.
It is not seen in fish liver oil.
It is heat stable.
It act as biological antioxidant.
It prevent oxidation of unsaturated fatty acids.
It required for normal physiology of muscular and vascular systems.
14. Deficiency of Vit.E in animals
Haemolysis of red blood cells
Muscular dystrophy
Decreased lipid synthesis
Decreased storage of Vit. A
Role of Vitamin E
It maintained the structural & functional features of smooth muscles, cardiac
muscles and skeletal muscles.
Facilitate better utilization of available Vit. A by preventing its oxidative
degradation.
Induction of essential cofactor in steroid metabolism.
15. D) Vitamin K( Phylloquinone)
It is required for normal blood coagulation.
It is needed for the formation of prothrombin.
Vit. K1 (phylloquinone) is found in plants, Vit. K2 (menaquinone) formed by
intestinal bacteria in animals.
It is antihemorrhagic vitamin.
17. 2. Water-Soluble Vitamins
(1) Thiamine (Vit.B1)
o It involved in carbohydrate metabolism.
o It occurs in fresh tissue as a pyrophosphate derivatives, which is active form
of thiamine.
18. oThiamine pyrophosphate (TPP) is a coenzyme of pyruvate decarboxylase enzymes.
oThis enzyme converts pyruvic acid to acetyl CoA.
oDeficiency of thiamine, pyruvate conc. Of blood & intercellular fluid rises.
oQuaternary nitrogen of thiamine is reaction centre during decarboxylation reaction.
oCoA is required for a function of cell like energy production via TCA cycle,
biosynthesis of fatty acids, steroids and glucose.
19. Deficiency of thiamine
oDeficiency of thiamine commonly called as Beri- Beri.
oIt affect the Nervous and circulatory systems.
oParalysis
oCardiovascular symptoms like, edema, loss of appetite.
20. (2) Riboflavin (Vit.B2)
oRiboflavin is required for biological redox system.
oTwo coenzyme of vitamin B2
a. Flavin mononucleotide (FMN)
b. Flavin Adenine Dinucleotide (FAD)
o FAD & FMN are prosthetic grp. Of oxidation reduction enzymes.
o Prosthetic grp. required for determination of amino acids.
21. Ex. Succinic acid dehydrogenase requires FAD as a prosthetic grp.
o Amino acids are oxidised to alpha-keto acid & ammonia.
22. ◦ Riboflavin is converted to its active form, FMN by an enzyme flavokinase.
Riboflavin + ATP FMN + ADP
◦ FAD is synthesized from FMN with the help of ATP
FMN + ATP FAD + PP
◦ Deficiency of vitamin B1 causes tongue inflammation i.e. glossitis.
23. (3) Nicotinic Acid (Niacin) Vit. B3
oObtained by the oxidation of nicotine.
oIt is organic compound with molecular formula C6H5NO2.
oSimple derivative of pyridine.
oWhite crystalline substance.
oIt is water soluble.
oResistant to heat, oxidation & alkalis.
oIt is most stable vitamin.
oEasily synthesised commercially.
24. ◦ Nicotinic acid is required for the formation of NAD+ and NAD+.
◦ It required for biological redox reaction.
NAD+ : Nicotinamide adenine dinucleotide
NADP+ : Nicotinamide adenine dinucleotide phosphate
25. i. Dehydrogenation of L-malate-
i. Dehydrogenation of glyceraldehyde 3-phosphate-
oThis reaction requires NAD+ as co-enzyme for glyceraldehyde 3-phosphate
dehydrogenase to give 1,3 diphosphate glycerate.
oIt reduced co-enzyme need for production of high energy like ATP.
26. Deficiency of Vit. B3
o Pellagra ( low level of vit.B3, Gi disorders)
o Black tongue disease( temporary condition due to over growth of bacteria or
fungi)
oDiarrhoea
oDementia (it cause by damage of brain cells)
oDermatitis (skin rashes, rashes)
27. (4) Pantothenic acid (B5)
o It required for formation of coenzyme A.
o Coenzyme required for metabolism of all acetate and fatty acid in the body.
28. Deficiency of Pantothenic acid (B5)
oGrowth failure
oDermatitis
oGraying and Loss of hair
oTissue necrosis ( death of tissue or injury)
oHemorrhages (loss of bleeding after surgery)
29. (5) Pyridoxine (Vit. B6)
oIt includes pyridoxine, pyridoxal and pyridoxamine.
oActive form of Vit.B6 is pyridoxal phosphate.
30. ◦ Pyridoxal phosphate is coenzyme for no. of reactions such as decarboxylase,
transamination, decarboxylase, tryptophanase cytothionase.
a. Transamination- Oxaloacetate is converted to aspartic acid.
- Glutamic acid is amino grp. Donor.
- Reaction is catalysed by transaminase.
31. b. Decarboxylation- Glutamic acid is decarboxylated to gama-amino butyric
acid by gultaminate decarboxylase.
C. Racemization- L-amino acid is converted to D amino acid.
L-glutamic acid Racemase D-glutamic acid
33. (6) Biotin ( Vitamin B7)
oIn animals, biotin is needed for the carboxylation reaction.
oThe molecular CO2 is fixed as carboxylic grp. In metabolite.
oIt needed for carboxylation.
o Enzyme called as carboxylase.
oEx. Carbonyl phosphate synthesis, carboxylation of acetyl CoA.
34. i. Formation of malonyl CoA- ii. Formation of carbonyl phosphate-
Deficiency of Vit. B7
oDecreases the biosynthesis of fatty acid.
35. (7) Folic acid (Vit. B9)
oFolic acid is made from pteridine ring, glutamic acid and p-amino acid
(PABA) in most bacteria.
o The active form of folic acid is tetrahydrofolate (THF).
oTHF act as coenzyme.
oThis enzyme transferring grp. Which contain one carbon such as formyl,
methyl, methylene, etc.
oBy using folic acid reductase folic acid converts its active form which
required co-enzyme (NADH + H+).
36. ◦ Metabolic reactions of THF are-
i) Glycine + N5N10 methylene THF Serine + THF
ii) Homocysteine + N15 methyl THF Methonine + THF
◦ THF enzyme is one carbon transfer reaction.
◦ It is important for metabolism.
◦ It required for growing and multiplying cells.
37. Deficiency of folic acid
o Anaemia
oIt can be treated by giving folic acid its called as Nutritional anaemia.
(8) Cyanocobalamin (Vit. B12)
oCo-enzyme B12 is active form of cyanocobalamin.
oCyanide ion is replaced by 5- deoxyadinosyl grp.
o2-types of reaction which needed co-enzyme B12-
38. a) 1, 2 shifts of hydrogen:
b) Methyl group transfer:
39. The structure of co-enzyme B12 –
oAbsorption of vit.B12 needs mucoprotein of gastric
juice called the intrinsic factor, it binds Vit.B12 and
transport the nutrients to intestinal cell.
Deficiency of Vit.B12 is anaemia.
40. (9) Lipoic acid
oIt is active supporting growth factor for bacteria and protozoa.
oIt contains fatty acids.
oIt is fat as well as water soluble.
oThe conversion of pyruvic acid or alpha-ketoglutaric acid by oxidative
decarboxylation reaction.
◦ Deficiency of lipoic acid
◦ Cysteine
◦ Taurine
41. Non B-Complex
Ascorbic acid (Vitamin C)
o It found in almost all fruits and vegetables.
o Citrus fruits and green vegetables contain a large quantity of Vit. C.
o It is strong reducing agent.
o It donates its two hydrogen to give dehydroascorbic acid.
o It act as co-enzyme for enzymic hydroxylation.
42. i) Formation of tyrosine
ii) It is required for the formation of hydroxy proline from proline.
iii) It required for cytochrome P 450 by which a Varity of organic compounds
are hydroxylated in liver.
Deficiency of Vit. C
oScurvy prolong deficiency of vit. C is known as scurvy. ( bleeding, swelling
wounds)
oAbnormal bone formation, joint pain
oBleeding of gums
43.
44. COENZYMES
◦ The non-protein, low molecular weight and organic substances associated
with functions of enzymes are called as coenzymes.
◦ This are small molecules.
◦ They cannot catalyse a reaction by themselves but they can help enzymes to
do.
◦ Ex. Thiamine pyrophosphate, FAD, etc.
◦ This are heat stable.
45. ◦ Vitamins are necessary for cell growth.
◦ Water soluble vitamins are converted to active form in the body.
◦ Active form of vitamins are co-enzymes.
◦ These derived from vitamins.
Table. Vitamins & Co-enzymes
Vitamins Co-enzymes
1. Thiamine (B1) Thiamine pyrophosphate (TPP)
2. Folic acid Tetra hydrofolate (THF)
3. Biotin Biotin
4. Riboflavin (B2) FMN and FAD