(一）饱和脂肪酸的合成 乙酰C0A 羧化 乙酰C0A羧化酶 +ATP+HCO, 丙二酰CoA 转移到 乙酰CoA +ACP ACP上 +ACP 乙酰ACP 丙二酰ACP 缩合 -C0, 乙酰乙酰ACP 还原 +NADPH 软脂酸 脱水 3-羟基丁酰ACP 磷脂酸 ◆-H,0 软脂CoA 还原 a,B-反式丁烯酰-ACP +NADPH⊥ 延长 丁酰ACP ◆.→软脂酰ACP 乙酰C0A一 ◆丙二酰ACP
α, β -反式丁烯酰-ACP 脱水 - H 2 O 3-羟基丁酰ACP 还原 +NADPH 乙酰CoA 丙二酰ACP 延长 软脂酰ACP -CO 2 乙酰乙酰ACP 缩合 丁酰ACP 还原 +NADPH 软脂酸 磷脂酸 软脂CoA 乙酰CoA 丙二酰CoA 乙酰CoA羧化酶 +ATP+HCO 3 - 羧化 + ACP 乙酰ACP + ACP 丙二酰ACP 转移到 乙酰CoA ACP 上 ( 一) 饱和脂肪酸的合成
乙酰C0A羧化酶 C02 R-CH2-COSCoA R-C-H-COSCoA H NH HCO3 HN N:C=O HN NH ATP ADP+Pi Carboxyl (CH2)4 Biotin (CH2)4 transferase (CH2)4 C=0 carboxylase C=0 AccA.AccD C-=0 NH AccC NH NH Lys Lys Lys CCP CCP CCP 韦物素我慧载体蛋息nteC.T体e step in fatty acid biosynthesis.The E.coli complex consists of four subunits.The three-letter designations are the products of the corresponding structural genes in E.coli
生物素羧基载体蛋白 乙酰CoA羧化酶
Proteins of the Fatty Acid Synthase Complex of E.coli Protein Role Acyl carrier protein (ACP) Carries acyl groups in thioester linkage Acetyl-CoA-ACP transacetylase (AT) Transfers acyl group from CoA to Cys residue of KS B-Ketoacyl-ACP synthase(KS) Condenses acyl and malonyl groups (there are at least three isozymes of KS) Malonyl-CoA-ACP transferase(MT) Transfers malonyl group from CoA to ACP B-Ketoacyl-ACP reductase (KR) Reduces 8-keto group to B-hydroxy group B-Hydroxyacyl-ACP dehydratase(HD) Removes H2O from 8-hydroxyacyl-ACP, creating double bond Enoyl-ACP reductase (ER) Reduces double bond,forming saturated acyl-ACP
KS MT Bacteria,Plants Seven activities AT ACP KR in seven separate polypeptides ER HD KS MT Yeast AT ACP Seven activities KR in two separate polypeptides ER HD KS MT Vertebrates AT ACP Seven activities KR in one large polypeptide ER HD
(一)饱和脂肪酸的合成 乙酰CoA 合成的 乙酰C04羧化酶 +ATP+HCO 调节 丙二酰C0A 乙酰CoA +ACP +ACP 乙酰ACP 丙二酰ACP -C02 乙酰乙酰ACP ATP水平 +NADPH 软脂酸 的调节 3-羟基丁酰ACP 磷脂酸 H20 软脂CoA a,B-反式丁烯酰-ACP +NADPH L 丁酰ACP 软脂酰ACP 乙酰C0A 丙二酰ACP
合成的 调节 ATP水平 的调节 (一) 饱和脂肪酸的合成