Axén E
Department of Pharmaceutical Biosciences, University of Uppsala, Sweden.
FEBS Lett. 1995 Nov 20;375(3):277-9. doi: 10.1016/0014-5793(95)01226-5.
A cytochrome P450 catalyzing 1 alpha-hydroxylation of 25-hydroxyvitamin D3 was purified from pig kidney microsomes. The enzyme preparation showed one protein band on gel electrophoresis with apparent M(r) of 52,500 and a specific cytochrome P450 content of 10.7 nmol/mg of protein. The 25-hydroxyvitamin D3 1 alpha-hydroxylase copurified with the vitamin D3 25-hydroxylase during purification. A cytochrome P450 catalyzing 1 alpha-hydroxylation was purified also from liver microsomes. The apparently homogeneous enzyme showed the same catalytic properties and apparent M(r) as the kidney enzyme. The results of the present communication demonstrate the presence in kidney of a previously unknown microsomal 1 alpha-hydroxylase in addition to the assumed specific mitochondrial 1 alpha-hydroxylase. The possibility that microsomal 1 alpha-hydroxylation in pig kidney and liver is catalyzed by the previously described porcine microsomal vitamin D 25-hydroxylase(s) is discussed.
从猪肾微粒体中纯化出一种催化25-羟基维生素D3 1α-羟化的细胞色素P450。该酶制剂在凝胶电泳上显示出一条蛋白带，表观分子量（M(r)）为52,500，细胞色素P450的比含量为10.7 nmol/mg蛋白质。在纯化过程中，25-羟基维生素D3 1α-羟化酶与维生素D3 25-羟化酶共纯化。还从肝微粒体中纯化出一种催化1α-羟化的细胞色素P450。这种明显均一的酶与肾酶具有相同的催化特性和表观分子量。本通讯的结果表明，除了假定的特异性线粒体1α-羟化酶外，肾脏中还存在一种以前未知的微粒体1α-羟化酶。讨论了猪肾和肝中的微粒体1α-羟化是否由先前描述的猪微粒体维生素D 25-羟化酶催化的可能性。
