Toda A, Ogata S, Nagamatsu A, Shimeno H
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Biochim Biophys Acta. 1993 Mar 1;1141(2-3):245-52. doi: 10.1016/0005-2728(93)90049-l.
Two diabetes-inducible forms of cytochrome P-450, named P-450ST-1 and -ST-2, were purified from the liver microsomes of streptozotocin-diabetic male rats by sodium cholate solubilization, octylamino-Sepharose 4B chromatography and high-performance liquid chromatography with DEAE-5PW and hydroxyapatite columns. The purified P-450 forms gave a single band each on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular weight of 48,500 for P-450ST-1 or 48,000 for P-450ST-2. The CO-reduced spectral maxima of P-450ST-1 and -ST-2 were at 451 nm. The two cytochromes had the low-spin state of heme in the oxidized form. Both P-450ST-1 and -ST-2 catalyzed the metabolism of aniline, benzphetamine, p-nitroanisole, testosterone and aminopyrine. However, the catalytic activity of P-450ST-2 for these substrates was apparently higher than that of ST-1. Analyses of the NH2-terminal amino-acid sequence and Western immunoblot showed that P-450ST-1 and -ST-2 differed structurally from each other. The catalytic activities, molecular weights, NH2-terminal sequences and/or immunochemical properties of P-450ST-1 and -ST-2 did not agree with those of the other cytochrome P-450 forms purified from diabetic rats previously.
通过胆酸钠增溶、辛基氨基琼脂糖4B层析以及使用DEAE - 5PW和羟基磷灰石柱的高效液相色谱法，从链脲佐菌素诱导的糖尿病雄性大鼠的肝脏微粒体中纯化出两种糖尿病诱导型细胞色素P - 450，分别命名为P - 450ST - 1和P - 450ST - 2。纯化后的P - 450形式在十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳上各呈现一条带，P - 450ST - 1的表观分子量为48,500，P - 450ST - 2的表观分子量为48,000。P - 450ST - 1和P - 450ST - 2的一氧化碳还原光谱最大值在451nm处。这两种细胞色素在氧化形式下具有血红素的低自旋态。P - 450ST - 1和P - 450ST - 2都催化苯胺、苄非他明、对硝基苯甲醚、睾酮和氨基比林的代谢。然而，P - 450ST - 2对这些底物的催化活性明显高于P - 450ST - 1。对氨基末端氨基酸序列的分析和蛋白质免疫印迹表明，P - 450ST - 1和P - 450ST - 2在结构上彼此不同。P - 450ST - 1和P - 450ST - 2的催化活性、分子量、氨基末端序列和/或免疫化学性质与先前从糖尿病大鼠中纯化出的其他细胞色素P - 450形式不一致。
