Metabolism of vitamin D3 by human CYP27A1
Metabolism of vitamin D3 by human CYP27A1
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DOI：
10.1006/bbrc.2000.3050
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发表时间：
2000-07-14
影响因子：
3.1
通讯作者：
Inouye, K
中科院分区：
文献类型：
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作者：
Sawada, N;Sakaki, T;Inouye, K
在大肠杆菌中表达了人维生素D-3 25-羟化酶（CYP27A1） cDNA，并对其酶学性质进行了分析。用重组大肠杆菌细胞制备的膜组分对重组体系进行了维生素d代谢的研究。令人惊讶的是，至少有八种形式的代谢物被观察到，包括主要产物25(OH)D-3。HPLC和质谱分析表明，这些代谢产物分别是25(OH) d - 3,26 (OW) d - 3,27 (OH) d - 3,24r,25(OH)(2) d - 3,1 α,25(OH)(2) d - 3,25,26 (OH)(2)D-3 (25,27(OH)(2)D-3)， 27-oxo-D-3和维生素D-3的脱氢形式。这些结果表明，人类CYP27A1催化了维生素D-3的多种反应和多步骤代谢。维生素D-3 25-羟基化和25(OH) d - 31 α -羟基化的K-m和V-max分别为3.2 μ M和0.27 (mol/min/mol P450)， 3.5 μ M和0.021 （mol/min/mol P450）。这些动力学研究使得评估CYP27A1催化的每个反应的生理意义成为可能。(C) 2000年学术出版社。
Human vitamin D-3 25-hydroxylase (CYP27A1) cDNA was expressed in Escherichia coli, and its enzymatic properties were revealed. The reconstituted system containing the membrane fraction prepared from the recombinant E. coli cells was examined for the metabolism of vitamin Ds. Surprisingly, at least eight forms of metabolites including the major product 25(OH)D-3 were observed. HPLC analysis and mass spectrometric analysis suggested that those metabolites were 25(OH)D-3, 26(OW)D-3, 27(OH)D-3, 24R,25(OH)(2)D-3, 1 alpha,25(OH)(2)D-3, 25,26(OH)(2)D-3 (25,27(OH)(2)D-3), 27-oxo-D-3 and a dehydrogenated form of vitamin D-3. These results suggest that human CYP27A1 catalyzes multiple reactions and multiple-step metabolism toward vitamin D-3. The K-m and V-max values for vitamin D-3 25-hydroxylation and 25(OH)D-3 1 alpha-hydroxylation were estimated to be 3.2 mu M and 0.27 (mol/min/mol P450), and 3.5 mu M and 0.021 (mol/min/mol P450), respectively. These kinetic studies have made it possible to evaluate a physiological meaning of each reaction catalyzed by CYP27A1. (C) 2000 Academic Press.