Phillips I R, Shephard E A, Bayney R M, Pike S F, Rabin B R, Heath R, Carter N
Biochem J. 1983 Apr 15;212(1):55-64. doi: 10.1042/bj2120055.
Two independent radioimmunoassay techniques for the major phenobarbital-inducible cytochrome P-450 (PB P-450) of rat liver microsomal membranes are described. The first technique employs as the source of radiolabelled antigen the products of translation in vitro labelled with [35S]methionine. The second technique employs purified antigen labelled with 125I and is quicker, less expensive and more precise. Both assays are highly specific for PB P-450 and can detect quantities of this variant as small as 1 ng. This is several orders of magnitude more sensitive than any method described previously for the quantification of cytochromes P-450, and consequently the technique is particularly well suited for the quantification of so-called constitutive cytochrome P-450 variants that are present in very low amounts. The results of the radioimmunoassays demonstrate that the apparent 2.6-fold induction of total cytochromes P-450 after phenobarbital treatment is due to a 43-fold increase in Pb P-450. Although beta-naphthoflavone increases the total content of cytochrome P-450 of microsomal membranes 1.4-fold, it actually causes a 55% decrease in the amount of PB P-450. Thus different xenobiotics can have differential effects on the expression of the genes for specific cytochrome P-450 variants.
本文描述了两种用于检测大鼠肝微粒体膜中主要苯巴比妥诱导型细胞色素P-450（PB P-450）的独立放射免疫分析技术。第一种技术使用经[35S]甲硫氨酸体外标记的翻译产物作为放射性标记抗原的来源。第二种技术使用用125I标记的纯化抗原，更快、更便宜且更精确。两种分析方法对PB P-450都具有高度特异性，能够检测低至1 ng的该变体数量。这比之前描述的任何细胞色素P-450定量方法灵敏几个数量级，因此该技术特别适用于定量存在量非常低的所谓组成型细胞色素P-450变体。放射免疫分析结果表明，苯巴比妥处理后细胞色素P-450总量的明显2.6倍诱导是由于Pb P-450增加了43倍。虽然β-萘黄酮使微粒体膜细胞色素P-450的总含量增加了1.4倍，但实际上导致PB P-450量减少了55%。因此，不同的外源性物质对特定细胞色素P-450变体基因的表达可能有不同的影响。
