维生素与辅酶

1. 维生素与辅酶 Vitamin And Cofactors of Enzyme

2. contents • introduction • Water-soluble Vitamins • Lipid-soluble Vitamins

3. 1 Introduction • Vitamins are essential nutrients that are required in the diet, usually in trace amounts, because they cannot be synthesized by the organism itself. • Necessary for maintenance of growth, health, metabolic homeostasis. • Dietary deficiency cause diseases——‘-penia’ s

4. 1.1Discoveryofvitamins： • Sun Simiao(孙思邈) Tang dynasty, Liver is applied to night-blindness( nyctalopia) Silverskin for beriberi(脚气病） • 1897 Dutch Dr. C. Eijkman Rice bran for beriberi • 1906 GB F. G. Hopkins Rats cannot survive on purified feed( including pr, fat, sacharides, minerals) Normal growth with trace milk Nutritional co-factors—— Vitamin。 without common chemical structure (aliphatic, aromatic, steroids and heterocyclic compound)

5. 1.2Classification of Vitamin • Fat-soluble vitamins: A, D, E, and K • Water-soluble vitamins: B complex vitamins, Folic acid and ascorbic acid, also known as vitamin C.

7. Fat-soluble vitamins • Participate in modulation of certain functions

8. Water-soluble Vitamins Co-enzymes that participate in group transfer

9. VA2 dehydroretinol VA1 retinol Retinol →retinal →retinoic acid 2 Fat-soluble Vitamins 2.1 Vitamin A——retinols

10. 2.2 Vitamin D (anti- osteomalacia ~) • 4 identified types: D2, D3, D4, D5 Most important of which are: • D2(麦角钙化醇ergocalciferol) • D3(胆钙化醇cholecaciferol) • Functions: To promotes Ca, P intake and osteogenesis • Active type: 1，25-dihydnxycholecalciferol

11. R VD2 VD3 VD4 VD5

12. vitamin D–binding protein (DBP), also known as transcalciferin Active form

13. The functions of1，25-dihydnxycholecalciferol • Participate in modulation of Ca-P balance (absorption, mobilization, osteogenesis and renal reuptake) • Elevate blood phosphorus and calcium concentration • Promote osteogenesis/ calcification 1，25-二羟胆钙化醇

14. 2.3 Vitamin E ( tocopherol) • Centchroman derivate • Nature structure: tocopherol & 生育三烯酚 Each type is divided, according to methyl number and position, into 8 kinds,α, β, γ, δ, etc. • α – tocopherol has the strongest activity

15. structure 母育酚（tocol） α-生育酚（α-tocopherol，5,7,8-trimethyltocol） β-生育酚（β-tocopherol，5,8-dimethyltocol） γ-生育酚（γ-tocopherol，7,8-dimethyltocol） δ-生育酚（δ-tocopherol，8-methyltocol） ζ2-生育酚（ζ2-tocopherol，5,7-dimethyltocol） η-生育酚（η- tocopherol，7-methyltocol） ε-生育酚（ε-tocopherol） ζ1-生育酚（ζ1-tocopherol）

16. Functions: • (1) Antioxidation ，protect unsaturated fatty acids in membranes . When human plasma levels are low, red blood cells are increasingly subject to oxidative hemolysis. • (2) Maintain procreative function. Deficiency causes ambloma.

17. Sourses: • Plant oil • Beans • vegetables

18. 2.4 Vitamin K • Naphthoquinone with isoprene sidechain • K1, K2, K3. K3 is synthetic. • K1、K2 are 2-ethyl -1,4- napthalene derived

19. Functions: To promote blood coagulation; Important factors in hepatic synthesis of thrombinogen and other blood coagulation factors .

20. Plasma thrombin thrombinogen Vitamin K thromboplastic protein Phospholipid, Ca2+ thrombin fibrae sanguis Unsoluble fibrin clot Carboxylation of Glu into γ-thrombinogen depends on enzymes with Vk

21. Structure: Vitamin K3

22. Source: • Food: • Vegetables, animal liver, fish • Milk, beans • Intestinal microorganisms

23. 3. Water-soluble vitamins and cofactors of enzyme

24. 3.1 Vitamin B1 Constitute of an amino pyrimidine ring and a sulfur-containing thiazole ring • Active form in vivo: • 焦磷酸硫胺素TPP( thiamine pyrophosphate)

25. Structure pyrimidine ring thiazole ring * *

26. Functions (1) Coenzyme for decarboxylases

27. (2) Coenzyme for transketolases

28. Properites: easy soluble in water, acidic. stable in acidic solution vulnerable to neutral and alkalic condition • Sources: Plant: cereals, beans Yeast • Unit∶ 1IU≈3μg pure VB1 hydrochloride

29. 3.2 Vitamin B2 and FMN, FAD • Vitamin B2 is also named as Riboflavin • Green fluorescent in solution • Part of prosthetic groups of oxidoreductase

30. Structure

31. FMN∶ Flavin mononucleotide黄素单核苷酸 • FAD∶Flavin Adenine Dinucleotide黄素腺嘌呤二核苷酸 • FMN, FAD——prosthetic groups——tightly bind to enzyme • Yellow →flavoprotein

32. Strong oxidant that is reduced by 1 or 2 atoms: H transfer

33. Functions： • Promote saccharide, lipid and protein metabolism as prosynthetic group. • Protect mucosa, maintain visual function, promote growth. • Deficiency: • Weak respiratory system, low metabolism rate • angular cheilitis(口角炎), glossitis(舌炎), conjunctivitis(结膜炎). • Min intake for adults: 1.6mg/d • No intoxication when overdosed. • Sources: • Wide existence in plants • Rice bran, yeast, liver, yolk, etc..

34. 3.3 Pantothenic acid (Vit. B3) & CoA-SH • Acidic compound of α, γ-dihydroxyl-β, β-dimethylbutyric acid β-alanine • phosphonic acid pantothenic acid β-cysteamine ↓ 4´-phosphopantetheine (4´-P-PaSH) + 5´-adenylate-3´- phosphonic acid ↓ CoA-SH (辅酶A） Sulfatidate bond faciliates hydrolization

35. Functions: • Participate in saccharide, lipid and protein metabolism in the form of CoA-SH • Participate in fatty acid metabolism as prosynthetic group of acyl carrier protein • Acyl carrier of acylation and oxydation decarboxylation（acyl- CoA：saccharide and lipid oxidation. • Synthesis of acetylcholine, cholesterol, glycogen, modulates blood lipid. • Effective to anorexia and debilitation • Ancillary drug for hepatitis and coronary heart disease

36. Sources: • Wide existence. • Liver, kidney, wheat, rice bran, yeast peanut.

37. 4. Nicotinic Acid and CoⅠ,CoⅡ • pellagra preventive factor or VPP Nicotinic Acid(烟酸) & Nicotinamide(烟酰胺)

38. structure: Oxidized form Reduced form NAD+ NADH energy yielding catabolism oxidized by respiratory chain NADP+ NADPH reductions in assimilation

40. Functions: • Participate in metabolism as coenzyme of anaerobic dehydrogenase H transfer • Maintain health of neural system. • Promote growth of microorganisms • Deficiency: • Pellagra , diarrhea, dementia • Sources: • Synthesized from Ser. • Yeast, liver, lean meat, milk, peanut, soybean

41. 3.5 VB6 • 吡哆醛pyridoxal • 吡哆胺pyridoxamine • 吡哆醇pyridoxine

42. structure: 磷酸吡哆醛磷酸吡哆胺

43. Functions (1) Transamination

44. (2) Decarboxylation

45. (3) Coenzyme of serine transhydroxymethylase for one-carbon unit transfer

46. 3.6 Biotin (Vit. B7) • Thiophene + urea • α-biotin（yolk） ——isopentoic acid side chain • β-biotin（liver） ——pentanoic acid side chain similar chemical and physiological characters • Wide existence in both animals and plants.

47. Co-enzyme/ prosynthetic group of carboxylase——CO2 fixation e.g. pyruvate carboxylase

48. 3.7 Folic acid (Vit. B11)& CoF • pterolyglutamic acid(PGA)