Cholesterol and hydroxycholesterol sulfotransferases: identification, distinction from dehydroepiandrosterone sulfotransferase, and differential tissue expression.
Cholesterol and hydroxycholesterol sulfotransferases: identification, distinction from dehydroepiandrosterone sulfotransferase, and differential tissue expression.
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DOI：
10.1210/endo.142.7.8244
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发表时间：
2001-07
期刊：
影响因子：
4.8
通讯作者：
N. Javitt;Y. C. Lee;C. Shimizu;H. Fuda;C. Strott
中科院分区：
文献类型：
--
作者：
N. Javitt;Y. C. Lee;C. Shimizu;H. Fuda;C. Strott
在人类中，胆固醇及其羟基化代谢物（氧固醇）通过磺化的生物转化是一个非常重要的基本过程。然而，执行该功能的磺基转移酶从未被明确鉴定。胆固醇是先前克隆的羟基类固醇磺基转移酶（HST），即脱氢表雄酮（DHEA）磺基转移酶（HST 1）的相对较差的底物。最近，有报道克隆了编码两种与HST 1相关的蛋白质的单个人类基因。这些新克隆的磺基转移酶（HST 2a和HST 2b），而表现出序列相似性的可溶性磺基转移酶超家族的其他成员，也包含独特的结构特征。后一个方面促使检查其底物特异性以与HST 1进行比较。因此，将HST 1、HST 2a和HST 2b作为融合蛋白过表达并纯化。此外，开发了一种分离胆固醇和氧化甾醇磺酸盐的新方法，该方法与HPLC结合使用，以解析特定的甾醇磺酸盐。HST 1优先磺化DHEA，并在较小程度上，氧固醇，而胆固醇是一个可以忽略不计的底物。然而，相反的情况是HST 2同种型，特别是HST 2b，其优先磺化胆固醇和氧固醇，与DHEA相反，DHEA作为该酶的不良底物。RT-PCR分析显示HST 1、HST 2a和HST 2b表达的不同模式。特别值得注意的是，两种HST 2亚型，而不是HST 1，在皮肤中表达，胆固醇磺化在皮肤屏障的正常发育中起重要作用的组织。总之，底物特异性和组织分布研究强烈表明，HST 2a和HST 2b，在HST 1相反，代表正常的人胆固醇和氧固醇磺基转移酶。此外，该研究代表了通过特定的人HST磺化氧固醇的第一个例子。
In humans, the biotransformation of cholesterol and its hydroxylated metabolites (oxysterols) by sulfonation is a fundamental process of great importance. Nevertheless, the sulfotransferase enzyme(s) that carries out this function has never been clearly identified. Cholesterol is a relatively poor substrate for the previously cloned hydroxysteroid sulfotransferase (HST), i.e. dehydroepiandrosterone (DHEA) sulfotransferase (HST1). Recently, cloning of a single human gene that encodes for two proteins related to HST1 was reported. These newly cloned sulfotransferases (HST2a and HST2b), while exhibiting sequence similarity to other members of the soluble sulfotransferase superfamily, also contain unique structural features. This latter aspect prompted an examination of their substrate specificity for comparison with HST1. Thus, HST1, HST2a, and HST2b were overexpressed as fusion proteins and purified. Furthermore, a novel procedure for the isolation of cholesterol and oxysterol sulfonates was developed that was used in association with HPLC to resolve specific sterol sulfonates. HST1 preferentially sulfonated DHEA and, to a lesser extent, oxysterols; whereas cholesterol was a negligible substrate. The reverse, however, was the case for the HST2 isoforms, particularly HST2b, which preferentially sulfonated cholesterol and oxysterols, in contrast to DHEA, which served as a poor substrate for this enzyme. RT-PCR analysis revealed distinct patterns of HST1, HST2a, and HST2b expression. It was particularly notable that both HST2 isoforms, but not HST1, were expressed in skin, a tissue where cholesterol sulfonation plays an important role in normal development of the skin barrier. In conclusion, substrate specificity and tissue distribution studies strongly suggest that HST2a and HST2b, in contrast to HST1, represent normal human cholesterol and oxysterol sulfotransferases. Furthermore, this study represents the first example of the sulfonation of oxysterols by a specific human HST.