VITAMIN

1. A B1 C D B3 B2 K B6 E STRUKTUR, FUNGSI DAN MEKANISMENYA B12 VITAMIN

2. Vitamin • Merupakan senyawa organik • Merupakan komponen dari bahan pakan • Terdapat dalam jumlah kecil • Esensial untuk pertumbuhan normal suatu jaringan, kesehatan, pertumbuhan dan pemeliharaan • Jika kekurangan menyebabkan gejala-gejala spesifik • Beberapa pada ternak tertentu disintesa oleh tubuh (sebagian besar tidak disintesa dalam tubuh)

3. Vitamin lanjutan • Digolongkan berdasarkan kesamaan fungsi umum dalam metabolisme • Umumnya terdapat di alam, dapat juga disintesa • Mempunyai ketahanan yang berbeda terhadap cahaya, oksigen, asam, basa dan panas

4. Ketahanan vitamin terhadap berbagai pengaruh

5. Ketahanan vitamin terhadap berbagai pengaruh (lanjutan)

6. KLASIFIKASI VITAMIN • Vitamin larutdalamlemak : A, D, E, K • Vitamin larutdalam air: B1 = tiamin B2 = riboflavin Asampantotenat Niasin = Niacinamide Biotin Folacin B6 = Pyridoxine, Pyridoxal, Pyridoxamin B12=Cyanocobalamin, Hydoxocobalamin, Aquocobalamin Choline Vitamin C = Ascorbic acid, L-ascorbic acid

7. Perbedaan Vitamin larut dalam lemak dan vitamin larut dalam air

8. Perbedaan Vitamin larut dalam lemak dan vitamin larut dalam air

9. Perbedaan Vitamin larut dalam lemak dan vitamin larut dalam air

10. VITAMIN ALAMI • Dalam bahan pakan jumlahnya sangat bervariasi dan tidak ada satu bahan pakan yang mengandung jumlah optimal untuk hewan. • Semua vitamin dibuat di tanaman dan diperoleh hewan apabila mengkonsumsi tanaman • Hewan mengandung mikroorganisme yang sanggup mensintesis vitamin larut dalam air, provitamin A dan menaquinone (Vitamin K2) • Vitamin B12 hanya bisa disintesis oleh mikro-organisme tertentu tidak bisa oleh tanaman ataupun hewan

11. KESTABILAN VITAMIN Kestabilan vitamin dipengaruhi juga oleh adanya antivitamin seperti : # Avidin yang ada pada putih telur akan mengikat biotin # Thiaminase pada ikan menghambat tiamin # l-amino-D-prolin pada flaxseed membentuk komplek stabil dengan pyridoxine

12. VITAMIN STABILITY CHARACTERISTIC A Oxidasi khususnya dengan Fe,Cu D3 Oxidasi (kestabilan sedang) E Stabil dalam bentuk acetat, sangat tidak stabildalam bentuk alcohol K Sangat tidak stabil Tiamin Sensitif terhadap oxidasi dan pH GENERAL VITAMIN STABILITY

13. VITAMIN STABILITY CHARACTERISTIC Pyridoksin, Kestabilan sedang riboflavin Pantotenat Sensitif hidrolisis Niasin Hampirstabil B12 Kestabilan tinggi, beberapa hilang bila kedaluwarsa Biotin Hampir stabil Asamfolat Kestabilan sedang, sensitif oxidasi dan reduksi Vitamin C Sangat tidak stabil dalam bentuk alami GENERAL VITAMIN STABILITY

14. VITAMIN LARUT DALAM LEMAK

15. Vitamin A (Retinol) R=CH2OH Retinol R=CH2OH Retinal R=CH2OH Asam Retinoat

16. Vitamin A (Retinol) Retinol

17. b - Caroteneand Retinol CH 3 CH CH CH 3 3 3 H C 3 CH 3 CH CH CH 3 3 3 CH 3 Oxidation CH CH O 3 3 H C CH 3 3 C H Retainal CH 3 - 2H CH CH 3 3 H C CH 3 3 CH OH 2 Retinol (Vitamin A) CH 3

18. Fungsi Vitamin A • Rangsangan cahaya dari mata ke otak • Berperan dalam sel epitel • Mengontrol aktivitas tulang

19. Opsin balok : rodopsin Opsin kerucut : iodopsin The vision cycle

20. Defisiensi Vitamin A • Buta malam • Seroptalamia (pengeringan & iritasi kornea, keruh dan mudah terinfeksi) • Terganggu sel

21. Vitamin D D2=Ergokalsiferol D3=Kholekalsiferol Pro Vit D2 = ergosterolPro Vit D3 = 7 dehidrokholesterol

22. Fungsi Vitamin D 1. Proses absorpsi 2. Proses reabsorpsi 3. Deposisi Defisiensi Vitamin D 1. Rakhitis 2. Osteomalasia

23. Vitamin E Vit E bentuk jenuhAlfatokoferol, Betatokoferol, Gamatokoferol, Deltatokoferol Vit E bentuk tidak jenuhAlfatokotrienol, Betatokotrienol, Gamatokotrienol, Deltatokotrienol

24. Fungsi Vitamin E 1. Reproduksi 2. Generasi 3. Hati dan Metabolisme 4. Memperbaiki absorpsi Fe 5. Antioksidan

25. Defisiensi Vitamin E 1. KemunduranReproduksi 2. Gangguanpermeabilitas 3. Kerusakanotot

26. Vitamin K K1 = FiloquinonK2 = MenaquinonK3 = Menadion Fungsi Vitamin K Koagulasi darah dengan mengaktifkan prothrombin (sintesis prothrombin didalam hati)

28. Thrombin Activation Fibrinogen + thrombin------------- Fibrin + Peptida

30. Defisiensi Vitamin K 1. Pembekuandarahterganggu

31. FUNGSI BIOKEMIS VITAMIN

32. VITAMIN LARUT DALAM AIR

33. Glc Glycogen G6P G1P R5P G3P Ala Pyr Acetyl-CoA Asp OA TCA cycle Glu aKG SCoA Vitamins in Metabolic Pathways Glycogenolysis PP a vit B6 Glycolysis PPP TK vit B1 ALT vit B6 PDH vit B1,B2,B3 AST vit B6 vit B6 aKGDH vit B1,B2,B3

34. Vitamin B1 Thiamine pyrophosphate (TPP) • Thiamine - a thiazole ring joined to a substituted pyrimidine by a methylene bridge • Thiamine-PP is the active form • TPP is involved in carbohydrate metabolism • It catalyzes decarboxylations of alpha-keto acids and the formation and cleavage of alpha-hydroxyketones

36. Thiamine Pyrophosphate Reactions and rationale • Yeast pyruvatedecarboxylase, acetolactatesynthase, transketolase, phosphoketolase • All these reactions depend on accumulation of negative charge on the carbonyl carbon at which cleavage occurs! • Thiamine pyrophosphate facilitates these reactions by stabilizing this negative charge • The key is the quaternary nitrogen of the thiazolium group

37. Riboflavin and the Flavins Vitamin B2 • All these substances contain ribitol and a flavin or isoalloxazine ring • Active forms are flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) • FMN is not a true nucleotide • FAD is not a dinucleotide • But the names are traditional and they persist!

39. Flavin Mechanisms Flavins are one- or two-electron transfer agents • Name "flavin" comes from Latin flavius for "yellow" • The oxidized form is yellow, semiquinones are blue or red and the reduced form is colorless • Study the electron and proton transfers in Figure 18.22 • Other transfers are possible!

40. Coenzyme A Pantothenic acid (vitamin B3) is a component of Coenzyme A • Functions: • Activation of acyl groups for transfer by nucleophilic attack • activation of the alpha-hydrogen of the acyl group for abstraction as a proton • Both these functions are mediated by the reactive -SH group on CoA, which forms thioesters

42. Nicotinic Acid and the Nicotinamide Coenzymes aka pyridine nucleotides • These coenzymes are two-electron carriers • They transfer hydride anion (H-) to and from substrates • Two important coenzymes in this class: • Nicotinamide adenine dinucleotide (NAD+) • Nicotinamide adenine dinucleotide phosphate (NADP+)

44. Nicotinamide Coenzymes Structural and mechanistic features • The quaternary nitrogen of the nicotinamide ring acts as an electron sink to facilitate hydride transfer • The site (on the nicotinamide ring) of hydride transfer is a pro-chiral center! • Hydride transfer is always stereospecific! • Be sure you understand the pro-R, pro-S designations

46. Last Notes on Nicotinamides • Nicotinamide was first isolated in 1937 by Elvehjem at the University of Wisconsin • Note similarities between structures of nicotinic acid, nicotinamide and nicotine • To avoid confusion of names (and functions!), the name niacin (for nicotinic acid vitamin) was suggested by Cowgill at Yale.

47. Biotin "Chemistry on a tether" • Biotin functions as a mobile carboxyl group carrier • Bound covalently to a lysine • The biotin-lysine conjugate is called biocytin • The biotin ring system is thus tethered to the protein by a long, flexible chain

49. Biotin Carboxylations Most use bicarbonate and ATP • Whenever you see a carboxylation that requires ATP and CO2 or HCO3-, think biotin! • Activation by ATP involves formation of carbonyl phosphate (aka carboxyl phosphate) • Carboxyl group is transferred to biotin to form N-carboxy-biotin • The "tether" allows the carboxyl group to be shuttled from the carboxylase subunit to the transcarboxylase subunit of ACC-carboxylase

50. Folic Acid Folates are donors of 1-C units for all oxidation levels of carbon except that of CO2 • Active form is tetrahydrofolate (THF) • THF is formed by two successive reductions of folate by dihydrofolatereductase • Know how to calculate oxidation states of C!