Vitamins and Microelements Introduction Definition 维生素(vitamin) 是机体维持正常功能所必需，但在体内不能合成或合成量很少，必须由食物供给的一组低分子量有机物质。Section I Lipid-soluble Vitamins 共同特点﹡均为非极性疏水的异戊二烯Isoprene 衍生物﹡不溶于水，溶于脂类及脂肪溶剂﹡在食物中与脂类共存，并随脂类一同吸收﹡吸收的脂溶性维生素在血液与脂蛋白及某些特殊结合蛋白特异结合而运输种类VitA, VitD, VitE, VitK Vitamin A （抗干眼病维生素）视紫红质的合成、分解与视黄醛的关系Vitamin E （Tocopherol ）（二）生化作用及缺乏症1. 抗氧化作用antioxidant ROO· RH ROOH R· （过氧化自由基）（多不饱和脂肪酸）（有机过氧化物）（有机自由基）R· O2 ROO· 在有维生素E(Vit E-OH) 存在时，它与有机过氧化自由基的反应为ROO·+Vit E-OH ROOH Vit E-O· 维生素E是一种断链抗氧化剂(chain-breaking antioxidant) 2. 维持生殖机能3. 促进血红素代谢Section ⅡWater-soluble Vitamins 一、有氧氧化的反应过程（一）丙酮酸的氧化脱羧Vitamin B2 (riboflavin) FMN 的文字结构式：6 、7二甲基异咯嗪核醇磷酸FAD 的文字结构式6 、7二甲基异咯嗪腺嘌呤核醇核糖磷酸磷酸Vitamin B3 (nicotin acid, nicotinamid, Vitamin PP) NAD+ 与NADP+ 的文字结构式尼克酰胺腺嘌呤核糖核糖-（磷酸）磷酸磷酸Vitamin B6 (pyridine derivatives) Biotin Vitamin B12 (cobalamin) ﹡生化作用：参与氧化还原反应，参与体内羟化应，促进胶原蛋白的合成，促进铁的吸收。﹡缺乏症：坏血病它与TPP 协同参与丙酮酸、α- 酮戊二酸的氧化脱羧反应，是α- 酮酸氧化脱羧反应中硫辛酸乙酰转移酶的辅酶,起转酰基作用13. Vitamin E (tocopherol) is the most important antioxidant in the body, acting in the lipid phase  of membranes throughout the cell. It protect the  effects of toxic radicals such as the peroxyl  radical, mainly as a breaker of free- radical chain  reactions. 14. Vitamin K is needed for the synthesis blood clotting  factors (eg, II, VII, IX, and X), as a cofactor to a  carboxylase that acts mate residues of clotting factor  precursor enable them to chelate calcium. Interrupt!  vitamin K regeneration cycle by dicumarol pounds  is the basis for their anticoagulanproperties. α-Lipoic acid 硫辛酸氧化型还原型（二）生化作用及缺乏症Summary 名称辅酶形式生理作用缺乏症硫胺素,维生素B1, 抗脚气病维生素硫胺素焦磷酸酯（TPP) a- 酮酸氧化脱羧酶的辅酶，磷酸戊糖旁路中转酮醇酶的辅酶脚气病维生素B2, 核黄素黄素腺嘌呤二核苷酸（FAD) 黄素单核苷酸(FMN) 黄素脱氢酶的辅酶口角炎舌炎维生素PP ，抗糙皮病维生素尼克酰胺腺嘌呤二核苷酸（NAD) 尼克酰胺腺嘌呤二核苷酸磷酸（NADP) 多数脱氢酶的辅酶，参与氢的传递糙皮病名称辅酶形式生理作用缺乏症维生素B6 吡哆醛磷酸吡哆醛转氨酶的辅酶，传递氨基氨基载体，肠菌能合成泛酸，遍多酸辅酶A 酰基转移生物素羧化酶的辅酶CO2 的载体抗生物素蛋白名称辅酶形式生理作用缺乏症维生素B12 叶酸四氢叶酸(FH4) 一碳单位的载体巨幼细胞性贫血甲基钴胺素，5- 脱氧钴胺素转甲基酶的辅酶巨幼细胞性贫血维生素C 抗坏血酸L抗坏血酸（还原）羟化反应坏血病硫辛酸SUMMARY Vitamins are all organic nutrients with various essential metabolic functions, required in small amounts in the diet because they cannot be synthesized by the body 2. Apart from vitamin C, the water-soluble vitamins are all members of the B complex and act as en-zyme cofactors 3. Thiamin is a cofactor in oxidative decarboxytion of a-keto acids and of an important enzyme the pentose phosphate pathway, transketolase 4. Riboflavin and niacin are each important cofactors in oxidoreduction reactions. Riboflavin is present as prosthetic groups in flavoprotein enzymes flavin mononucleotide and flavin adenine dirnucleotide, whereas niacin is present in the NAD and NADP cofactors of many dehydrogenase enzymes. 5. Pantothenic acid is present in coenzyme A and acyl carrier protein, which act as carriers for a groups in many important reactions, whereas pydoxal phosphate is the coenzyme for several enzyme of amino acid metabolism including the transaminases. 6.Biotin is the coenzyme for several carboxylase enzymes, including acetyl-CoA carboxylase, the rate controlling enzyme in lipogenesis, and pyruvate carboxylase, important in gluconeogenesis. 7. As well as having separate functions, vitamine B12 and folic acid take part in providing one-carbon residues for nucleic acid synthesis. 8.Ascorbic acid is a water-soluble antioxidant that maintains many metal cofactors in the reduced state 9. Absence of the water-soluble vitamins from the diet provokes multiple deficiency states. Absence a single vitamin leads to a characteristic deficiency syndrome. 10 .The lipid-soluble vitamine have the common features of being apolar, hydrophobic molecules and also of being isoprene derivatives. They all require normal fat absorption to be occurring for efficient absorption, and if this mechanism is defective, defi-ciency symptoms are likely to occur. 11. Vitamin A (retinol) is represented not only as such in the diet but also by the provitamin (P-carotene) in plants. Retinol and retinoic acid are con-sidered to act by controlling gene expression, whereas retinal is utilized in vision and has a role in glycoprotein synthesis. 12. Vitamin D is a steroid prohormone whose activity  is carried out by its hormone derivative. It is utilized in the regulation of calcium and  phos-phate metabolism, and its omission from  the diet leads to rickets and osteomalacia. Vit B2 FMN AMP FAD ⅠⅡⅢ（二）生化作用及缺乏症﹡生化作用：FMN 及FAD 是体内氧化还原酶的辅基，主要起氢传递体的作用。﹡缺乏症：口角炎cheilosis ，唇炎，阴囊炎等。（一）化学本质及性质﹡维生素PP 包括尼克酸(nicotinic acid) 尼克酰胺(nicotinamide) ﹡体内活性形式尼克酰胺腺嘌呤二核苷酸(NAD+) nicotinamideadenine dinucleotide 尼克酰胺腺嘌呤二核苷酸磷酸(NADP+) nicotinamide adenine dinucleotide phosphate NAD+ ：R为H NADP+ ：R为（二）生化作用及缺乏症1. 生化作用﹡NAD+ 及NADP+ 是体内多种脱氢酶（如苹果酸脱氢酶、乳酸脱氢酶）的辅酶，起传递氢的作用。2. 缺乏症﹡癞皮病（一）化学本质及性质﹡维生素B6 包括吡哆醇pyridoxine ，吡哆醛pyridoxal 及吡哆胺Pyridoxamine ﹡体内活性形式为磷酸吡哆醛和磷酸吡哆胺（二）生化作用及缺乏症﹡磷酸吡哆醛是氨基酸转氨酶及脱羧酶的辅酶，也是-氨基-酮戊酸合酶（ALA 合酶）的辅酶。Vitamin B5  (pantothenic acid) （一）化学本质及性质﹡泛酸(pantothenic acid) 又名遍多酸﹡体内活性形式为辅酶A(CoA) 酰基载体蛋白(ACP) （二）生化作用及缺乏症﹡CoA 及ACP 是酰基转移酶的辅酶，参与酰基的转移作用。CoA 的结构式泛酸4- 磷酸泛酰巯基乙胺生化作用生化作用生物素(biotin) 是多种羧化酶（如丙酮酸羧化酶）的辅酶，参与CO2 的羧化过程。与赖氨酸残基ε- 氨基结合成生物胞素与羧基结合生成羧基生物素Folic acid （一）化学本质及性质﹡叶酸(folic acid) 又称蝶酰谷氨酸﹡体内活性形式为四氢叶酸(FH4) tetrahydrofolate 蝶酰谷氨酸叶酸二氢叶酸还原酶NADPH+H+ NADP+ 二氢叶酸二氢叶酸还原酶NADPH+H+ NADP+ 四氢叶酸5, 6, 7, 8- 四氢叶酸目录（二）生化作用及缺乏症﹡生化作用：FH4 是一碳单位转移酶的辅酶，参与一碳单位的转移。﹡缺乏症：巨幼红细胞贫血Megaloblastic anemia 临床应用抗肿瘤药物，抑制四氢叶酸合成,dUMP, dTMP 磺胺药的作用，叶酸合成障碍（一）化学本质及性质﹡维生素B12 又称钴胺素(coholamine) ﹡体内活性形式为甲基钴胺素5 -脱氧腺苷钴胺素R：-CH3 甲基钴胺素R ：5`- 脱氧腺苷5`- 脱氧腺苷钴胺素（二）生化作用及缺乏症﹡生化作用：参与体内甲基转移作用﹡缺乏症：巨幼红细胞贫血Megaloblastic anemia 、神经疾患High blood level of homocysteine Vitamin C (ascorbic acid) （一）化学本质及性质﹡维生素C又称L- 抗坏血酸(ascorbic acid) 维生素C 脱氢维生素C （二）生化作用及缺乏症* * 脂溶性维生素(lipid-soluble vitamin) 水溶性维生素(water-soluble vitamin) 分类: 13 Essential Vitamins For Human Being vitamins water -soluble lipid-soluble Vit C Vit B A,D,E,K B1, B2, B6, B12, PP, patothenic acid ，folic acid,biotin ,lipoic acid （一）化学本质与性质﹡天然形式：A1 （retinol ）A2 （3- 脱氢视黄醇）﹡活性形式：视黄醇、视黄醛、视黄酸﹡维生素A原：β- 胡萝卜素（二）生化作用及缺乏症1. 生化作用＊构成视觉细胞内感光物质（见后图）＊参与糖蛋白的合成，维持上皮组织的分化与健全＊其他作用，如影响细胞的分化2. 缺乏症夜盲症night blindness, 干眼病dry eyes ，皮肤干燥dry skin 等视紫红质视蛋白11- 顺视黄醛全反视黄醛暗处光(视网膜) 异构酶11- 顺视黄醇全反视黄醇(肝) 异构酶视黄醛还原酶Vitamin D （抗佝偻病维生素） （一）化学本质和性质﹡种类：VitD2 （麦角钙化醇）VitD3 （胆钙化醇）﹡VitD2 原：麦角固醇VitD3 原：7- 脱氢胆固醇麦角固醇→VitD2 胆固醇→7- 脱氢胆固醇→VitD3 ﹡VitD3 的活性形式：1, 25- (OH)2-VitD3 OH OH 肝25- 羟化酶维生素D3 （胆钙化醇）25- 羟维生素D3 （25- 羟胆钙化醇）肾,骨,胎盘中的1α- 羟化酶1, 25- 二羟维生素D3 （1, 25- 二羟胆钙化醇