Characterization of rat and human CYP2J enzymes as Vitamin D 25-hydroxylases

Aiba Isamu

Yamasaki Tomoaki

Shinki Toshimasa

Izumi Shunsuke

Yamamoto Keiko

Yamada Sachiko

Terato Hiroaki

Ide Hiroshi

Ohyama Yoshihiko

Steroids

vitamin D is 25-hydroxylated in the liver, before being activated by 1α-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 D3 25-hydroxylase. J Biol Chem 2004;279(22):22848-56]. In this study, we examine whether human CYP2J2 that exhibits 73 0x1.39bf8p-890mino 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 D3 (turnover number, 0.087 min-1), vitamin D2 (0.16 min-1), and 1α-hydroxyvitamin D3 (2.2 min-1). Interestingly, human CYP2J2 hydroxylated vitamin D2, an exogenous vitamin D, at a higher rate than it did vitamin D3, an endogenous vitamin D, whereas, rat CYP2J3 hydroxylated vitamin D3 (1.4 min-1) more efficiently than vitamin D2 (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 D3 and D2. c 2006 Elsevier Inc. All rights reserved.

25-Hydroxylase

CYP2J2

CYP2J3

vitamin D2

vitamin D3

Biology [ 460 ]

eng

Elsevier Inc

Copyright (c) 2006 Elsevier Inc.

[Created] 2006

[DOI] 10.1016/j.steroids.2006.04.009

[ISSN] 0039-128X

[NCID] AA00850124

[PMID] 16842832

[DOI] http://dx.doi.org/10.1016/j.steroids.2006.04.009 isVersionOf