成年仓鼠组织匀浆对甘氨鹅去氧胆酸的酶促硫酸化作用。

Enzymatic sulfation of glycochenodeoxycholic acid by tissue fractions from adult hamsters.

作者信息

Barnes S, Burhol P G, Zander R, Haggstrom G, Settine R L, Hirschowitz B I

出版信息

J Lipid Res. 1979 Nov;20(8):952-9.

Abstract

Using a radiometric assay with glycochenodeoxycholic acid as substrate, bile acid:3'-phosphoadenosine-5'-phosphosulfate sulfotransferase activity was found in 105,000 g supernatant fractions of liver, proximal intestine, and adrenal gland homogenates from adult hamsters. Optimum conditions for measurement of the hepatic enzyme were determined. In both male and female animals sulfation only occurred at the 7 alpha-position. Saturation analysis with glycohenodeoxycholic acid revealed that the higher activity observed in fractions from female compared to male hamsters was due to a 4-fold lower apparent Km (79 muM vs. 317 muM) for this bile acid in the females. The sulfation of glycohenodeoxycholic acid was competitively inhibited by glycolithocholic acid, chenodeoxycholic acid, and ursodeoxycholic acid. The data are consistent with the concept that sulfation of many, if not all, bile acids can occur in vivo.

摘要

使用以甘氨鹅脱氧胆酸为底物的放射性测定法，在成年仓鼠肝脏、近端肠道和肾上腺匀浆的105,000g上清液组分中发现了胆汁酸：3'-磷酸腺苷-5'-磷酸硫酸转移酶活性。确定了肝脏酶测量的最佳条件。在雄性和雌性动物中，硫酸化仅发生在7α位。用甘氨鹅脱氧胆酸进行的饱和分析表明，与雄性仓鼠相比，雌性仓鼠组分中观察到的较高活性是由于雌性动物中该胆汁酸的表观Km（79μM对317μM）低4倍。甘氨鹅脱氧胆酸的硫酸化受到甘氨石胆酸、鹅脱氧胆酸和熊去氧胆酸的竞争性抑制。这些数据与许多（如果不是全部）胆汁酸在体内可发生硫酸化的概念一致。