第二节脂肪酸的合代谢
第二节 脂肪酸的合成代谢
.甘油的合成 甘油的合成在细胞质中进行。 由糖酵解的中间产物磷酸二羟丙酮还原而成。 HC-OH NADHH NAD H2C-OH HO H2C-OH HO-CH HO-CH HC-0p0磷酸甘油脱氨酶C-0P03碜酸酯酶 HIC-OH 磷酸二羟丙酮 磷酸甘油 甘油 事实上,在甘油和脂肪酸缩合连结成脂肪时, 所需要的是3-磷酸甘油,而不是游离的甘油
一. 甘油的合成 由糖酵解的中间产物磷酸二羟丙酮还原而成。 甘油的合成在细胞质中进行。 事实上，在甘油和脂肪酸缩合连结成脂肪时， 所需要的是3-磷酸甘油，而不是游离的甘油
(一)脂肪酸的从头合成 脂肪酸的合成 部位: 动物体—细胞质 植物体—叶绿体和前质体 原料:乙酰CoA 产物:不超过16碳的饱和脂肪酸
(一) 脂肪酸的从头合成 二. 脂肪酸的合成 原料：乙酰CoA 产物：不超过16碳的饱和脂肪酸 部位： 动物体 —— 细胞质 植物体 —— 叶绿体和前质体
(一)脂肪酸的从头合成 脂肪酸的合成 Overview Fatty acids are synthesized by the condensation of two-carbon units. However in terms of the enzymic steps involved, the process is not the reversed of B-oxidation Fatty acid synthesis involves a separate series of reactions to build up long-chain hydrocarbons from acetyl CoA units. The key differences between fatty acid synthesis and breakdown are:
Overview Fatty acids are synthesized by the condensation of two-carbon units. However, in terms of the enzymic steps involved, the process is not the reversed of -oxidation. Fatty acid synthesis involves a separate series of reactions to build up long-chain hydrocarbons from acetyl CoA units. The key differences between fatty acid synthesis and breakdown are: (一) 脂肪酸的从头合成 二. 脂肪酸的合成
(一)脂肪酸的从头合成 脂肪酸的合成 1. fatty acid synthesis occurs in the cytosol of both prokaryotes and eukaryotes whereas their degradation occurs in the mitochondria of euKaryotes 2. fatty acid synthesis uses NADPh as the reductant whereas nadh is produced in B-oxidation 3. during their synthesis, fatty acids are covalent linked to an acyl carrier protein(ACP), as opposed to CoA in their degradation 4. the enzyme activities of fatty acid synthesis in higher organisms are present in a single polypeptide chain called fatty acid synthase, whereas in B-oxidation the individual activities are present on separate enzymes
1. fatty acid synthesis occurs in the cytosol of both prokaryotes and eukaryotes whereas their degradation occurs in the mitochondria of eukaryotes; 2. fatty acid synthesis uses NADPH as the reductant whereas NADH is produced in -oxidation; 3. during their synthesis, fatty acids are covalently linked to an acyl carrier protein (ACP), as opposed to CoA in their degradation; 4. the enzyme activities of fatty acid synthesis in higher organisms are present in a single polypeptide chain called fatty acid synthase, whereas in -oxidation the individual activities are present on separate enzymes. (一) 脂肪酸的从头合成 二. 脂肪酸的合成