Characterization of rat and human CYP2J enzymes as vitamin D 25-hydroxylases
Characterization of rat and human CYP2J enzymes as vitamin D 25-hydroxylases
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DOI：
10.1016/j.steroids.2006.04.009
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发表时间：
2006-10-01
期刊：
影响因子：
2.7
通讯作者：
Ohyama, Yoshihiko
中科院分区：
文献类型：
--
作者：
Aiba, Isamu;Yamasaki, Tomoaki;Ohyama, Yoshihiko
维生素D在肝脏中被25-羟基化，然后在肾脏中被1 -羟基化激活。最近，大鼠细胞色素P450 2J3 （CYP2J3）已被确定为大鼠体内主要的维生素D- 25羟化酶[Yamasaki T， Izumi S, Ide H, Ohyama Y]。中国生物医学工程学报（英文版）；2004;31(2):448 - 456。在这项研究中，我们研究了与大鼠CYP2J3具有73%氨基酸同源性的人CYP2J2是否具有类似的催化性能。重组人CYP2J2在大肠杆菌中过表达，纯化，并测定维生素D 25-羟基化活性。我们发现对维生素D-3（周转时间，0.087 min(-1)）、维生素D-2 （0.16 min(-1)）和1 α -羟基维生素D-3 （2.2 min(-1)）具有显著的25-羟基化活性。有趣的是，人类CYP2J2羟基化维生素D-2（一种外源性维生素D）的速度高于维生素D-3（一种内源性维生素D），而大鼠CYP2J3羟基化维生素D-3（1.4分钟（-1））的效率高于维生素D-2（0.86分钟（-1））。我们的研究表明，人CYP2J2和大鼠CYP2J3一样具有25-羟基化活性，尽管人CYP2J2的活性比大鼠CYP2J3弱。CYP2J2和CYP2J3对维生素D-3和D-2表现出明显的偏好。(c) 2006爱思唯尔公司版权所有。
Vitamin D is 25-hydroxylated in the liver, before being activated by 1 alpha-hydroxylation in the kidney. Recently, the rat cytochrome P450 2J3 (CYP2J3) has been identified as a principal vitamin D 25-hydroxylase in the rat [Yamasaki T, Izumi S, Ide H, Ohyama Y Identification of a novel rat microsomal vitamin D-3 25-hydroxylase. J Biol Chem 2004;279(22):22848-56]. In this study, we examine whether human CYP2J2 that exhibits 73% amino acid homology to rat CYP2J3 has similar catalytic properties. Recombinant human CYP2J2 was overexpressed in Escherichia coli, purified, and assayed for vitamin D 25-hydroxylation activity. We found significant 25-hydroxylation activity toward vitamin D-3 (turnover number, 0.087 min(-1)), vitamin D-2 (0.16 min(-1)), and 1 alpha-hydroxyvitamin D-3 (2.2 min(-1)). Interestingly, human CYP2J2 hydroxylated vitamin D-2, an exogenous vitamin D, at a higher rate than it did vitamin D-3, an endogenous vitamin D, whereas, rat CYP2J3 hydroxylated vitamin D-3 (1.4 min(-1)) more efficiently than vitamin D-2 (0.86 min(-1)). Our study demonstrated that human CYP2J2 exhibits 25-hydroxylation activity as well as rat CYP2J3, although the activity of human CYP2J2 is weaker than rat CYP2J3. CYP2J2 and CYP2J3 exhibit distinct preferences toward vitamin D-3 and D-2. (c) 2006 Elsevier Inc. All rights reserved.