Lecture07_Vitamins, coenzymes and trace elements维生素.pdf

第七章 维生素和辅酶 及微量元素 Vitamins, Coenzymes and Trace Elements 1 Objectives 1. Identify water- and fat-soluble vitamins 2. Define coenzymes and cofactors 3. Understand the metal ions that act as cofactors in enzymatic reactions 4. Describe the roles of vitamins and their involvement as coenzymes 2 Vitamins What are vitamins? o The term vitamin is derived from the phrase vital amine. o essential substances that cannot be manufactured by the body. o Small amounts of vitamins are needed for growth and development. oWithout vitamins the body cannot survive. Types: • Water-soluble vitamins • Fat-soluble vitamins RDA (recommended daily allowance ) 3 Water-Soluble Vitamins Water-soluble vitamins are  Soluble in aqueous solutions.  Cofactors for many enzymes.  Not stored in the body.  B , B , B , B , B , B , C, Biotin(生物 1 2 3 5 6 12 素) and Folic acid(叶酸). 4 Water-Soluble Vitamins  易溶于水，故易随尿液排出  体内不易储存，必须经常从食物中摄取  作用比较单一，主要构成酶的辅助因子直接影 响某些酶的催化作用。  种类：B族维生素，维生素C Fat-Soluble Vitamins Fat-soluble vitamins are  Vitamins A, D, E, and K.  Soluble in lipids, but not in aqueous solutions.  Important in vision, bone formation, antioxidants, and blood clotting.  Stored in the body. 6 Fat-Soluble Vitamins （1）不溶于水，溶于脂肪及有机溶剂 （2）在食物中与脂类共存，并随脂类一同吸收 （3）吸收的脂溶性维生素在血液中与脂蛋白及某些 特殊结合蛋白特异结合而运输 （4）可在肝脏内储存，若摄入过多会出现中毒症状 种类：维生素A 、D、E、K Learning Check Identify each compound as a water-soluble vitamin (W) fat-soluble vitamin (F) 1. Folic