日本麝鼩（Suncus murinus）中的细胞色素P-450依赖性脂肪酸羟化酶系统。

Cytochrome P-450-dependent fatty acid hydroxylase system in Japanese house musk shrew, Suncus murinus.

作者信息

Miura Y, Hisaki H, Oda S

出版信息

J Biochem. 1984 Mar;95(3):779-84. doi: 10.1093/oxfordjournals.jbchem.a134669.

DOI:10.1093/oxfordjournals.jbchem.a134669

Abstract

The substrate specificity and other properties of a fatty acid hydroxylase system in liver microsomes of the Japanese house musk shrew, Suncus murinus, were examined. Shrew liver microsomes catalyzed the hydroxylation of various saturated fatty acids (C8-C18) to the corresponding omega- and (omega-1)-hydroxy derivatives. The relative activities of the hydroxylase with these substrates were as follows: C12 (100, actual conversion: 7.05 nmol/mg of microsomal protein/min), C10 (90), C14 (87), C16 (23), C8 (19), and C18 (11). The specific activity of the fatty acid hydroxylase in shrew liver was much higher than that in other species. The omega/omega-1-hydroxylation ratio decreased with increasing chain length of fatty acid substrates (C10-C18), but it was 0 for the C8 fatty acid. Both NADPH and O2 were required for hydroxylase activity, and NADH had little effect. The apparent Km value for laurate was 1.6 X 10(-5) M. The hydroxylase activity was 92% inhibited by CO at a CO-O2 ratio of 9. p-Chloromercuribenzoate (0.1 mM) inhibited hydroxylation by 94% whereas iodoacetate (0.1 mM) inhibited it by only 8%. SKF 525-A (1 mM) and menadione (0.01 mM), respectively, caused 41% and 29% inhibition of the activity. It is concluded that the hydroxylase catalyzing fatty acid hydroxylation in shrew liver microsomes is a typical cytochrome P-450-linked monooxygenase.

摘要

对日本麝鼩（Suncus murinus）肝脏微粒体中脂肪酸羟化酶系统的底物特异性及其他特性进行了研究。麝鼩肝脏微粒体可将各种饱和脂肪酸（C8 - C18）羟基化为相应的ω-和（ω-1）-羟基衍生物。羟化酶对这些底物的相对活性如下：C12（100，实际转化率：7.05 nmol/mg微粒体蛋白/分钟），C10（90），C14（87），C16（23），C8（19）和C18（11）。麝鼩肝脏中脂肪酸羟化酶的比活性远高于其他物种。随着脂肪酸底物链长增加（C10 - C18），ω/ω-1-羟基化比率降低，但对于C8脂肪酸，该比率为0。羟化酶活性需要NADPH和O2，而NADH影响很小。月桂酸的表观Km值为1.6×10（-5）M。在CO - O2比率为9时，CO对羟化酶活性的抑制率为92％。对氯汞苯甲酸（0.1 mM）对羟基化的抑制率为94％，而碘乙酸（0.1 mM）仅抑制8％。SKF 525 - A（1 mM）和甲萘醌（0.01 mM）分别导致活性抑制41％和29％。得出的结论是，催化麝鼩肝脏微粒体中脂肪酸羟化的羟化酶是一种典型的细胞色素P - 450连接的单加氧酶。