1. Characterization of rat and human CYP2J enzymes as Vitamin D 25-hydroxylases
- Author
-
Sachiko Yamada, Shunsuke Izumi, Keiko Yamamoto, Hiroshi Ide, Yoshihiko Ohyama, Isarnu Aiba, Tomoaki Yamasaki, Hiroaki Terato, and Toshimasa Shinki
- Subjects
vitamin D3 ,vitamin D2 ,Clinical Biochemistry ,Biology ,medicine.disease_cause ,Biochemistry ,CYP2J2 ,Endocrinology ,Cytochrome P-450 Enzyme System ,medicine ,Vitamin D and neurology ,Animals ,Humans ,Molecular Biology ,Escherichia coli ,DNA Primers ,Pharmacology ,chemistry.chemical_classification ,Base Sequence ,Organic Chemistry ,Cytochrome P450 ,25-Hydroxylase ,Vitamin D-dependent calcium-binding protein ,Recombinant Proteins ,Rats ,Ergocalciferol ,Enzyme ,chemistry ,biology.protein ,Microsome ,Cholestanetriol 26-Monooxygenase ,CYP2J3 ,medicine.drug - Abstract
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.
- Published
- 2006