大鼠胃黏膜对胆固醇的酶促硫酸化作用。

Enzymatic sulfation of cholesterol by rat gastric mucosa.

作者信息

Lin Y N, Horowitz M I

出版信息

Steroids. 1980 Dec;36(6):697-708. doi: 10.1016/0039-128x(80)90052-5.

Abstract

A sulfotransferase which catalyzes transfer of the sulfate group from 3'-phosphoadenosine-5'phosphosulfate to cholesterol has been demonstrated in the rat gastric mucosa. The product of the reaction was characterized as cholesterol sulfate by two-dimensional thin-layer chromatographic behavior, and gas-liquid chromatography of cholesterol after acid solvolysis. The bulk of enzyme activity was found in the cytosol fraction. Sulfation of cholesterol did not require added Mg+2, Mn+2, or Ca+2, and was unaffected by ethylenediaminetetraacetate. Triton X-100 moderately enhanced the enzyme activity. A broad pH optimum from pH 6.0-9.0 was exhibited with a maximum at pH 7.0-7.5. The apparent Km for PAPS was 0.8 x 10(-6)M. The possible function of cholesterol sulfate in gastric mucosa is discussed.

摘要

在大鼠胃黏膜中已证实有一种硫酸转移酶，它能催化将硫酸基团从3'-磷酸腺苷-5'-磷酸硫酸转移至胆固醇。通过二维薄层色谱行为以及酸解后胆固醇的气液色谱分析，反应产物被鉴定为硫酸胆固醇。大部分酶活性存在于胞质溶胶部分。胆固醇的硫酸化不需要添加Mg²⁺、Mn²⁺或Ca²⁺，且不受乙二胺四乙酸影响。Triton X-100适度增强了酶活性。在pH 6.0 - 9.0范围内呈现出较宽的最适pH，在pH 7.0 - 7.5时活性最高。PAPS的表观Km为0.8×10⁻⁶M。文中讨论了硫酸胆固醇在胃黏膜中的可能功能。