Shephard E A, Phillips I R, Bayney R M, Pike S F, Rabin B R
Biochem J. 1983 May 1;211(2):333-40. doi: 10.1042/bj2110333.
We have developed a specific radioimmunoassay to quantify NADPH: cytochrome P-450 reductase. The assay is based on the use of 125I-labelled NADPH: cytochrome P-450 reductase as the radiolabelled antigen and can detect quantities of this protein in amounts as low as 30 pg. The results of the radioimmunoassay demonstrates that the 2.7-fold increase in enzyme activity in rat liver microsomal membranes after phenobarbital treatment is due to increased amounts of the protein. beta-Naphthoflavone treatment, however, did not alter the activity or the quantity of this enzyme in microsomes. The quantification of NADPH: cytochrome P-450 reductase in the microsomes isolated from control and phenobarbital- and beta-naphthoflavone-treated animals permits the calculation of the ratio of this protein to that of total cytochromes P-450. A molar ratio of 15:1 (cytochromes P-450/NADPH: cytochrome P-450 reductase) was calculated for control and phenobarbital-treated animals. This ratio increased to 21:1 after beta-naphthoflavone treatment. Thus the molar ratio of these proteins in liver microsomes can vary with exposure of the animals to particular xenobiotics.
我们开发了一种特定的放射免疫分析法来定量测定NADPH：细胞色素P-450还原酶。该分析方法基于使用125I标记的NADPH：细胞色素P-450还原酶作为放射性标记抗原，能够检测低至30 pg量的这种蛋白质。放射免疫分析结果表明，苯巴比妥处理后大鼠肝微粒体膜中酶活性增加2.7倍是由于该蛋白质含量增加。然而，β-萘黄酮处理并未改变微粒体中该酶的活性或含量。对从对照动物以及经苯巴比妥和β-萘黄酮处理的动物中分离出的微粒体中的NADPH：细胞色素P-450还原酶进行定量，可计算出该蛋白质与总细胞色素P-450的比例。对照动物和经苯巴比妥处理的动物的摩尔比为15:1（细胞色素P-450/NADPH：细胞色素P-450还原酶）。β-萘黄酮处理后该比例增至21:1。因此，肝微粒体中这些蛋白质的摩尔比会随动物接触特定外源化学物的情况而变化。
