Hammond D K, Strobel H W
Department of Biochemistry and Molecular Biology, University of Texas, Houston 77225.
Mol Cell Biochem. 1990 Mar 27;93(2):95-105. doi: 10.1007/BF00226181.
The effects of culture variables on the specific content and activity of various enzymes of the drug metabolizing system were assessed in colon tumor cell line LS174T. The NADH reduced cytochrome b5 (cyt b5)4 spectrum of these cells was similar to rat liver cyt b5. When released from the membrane by trypsin and concentrated, the cyt b5 was found to cross react with rabbit antibody to rat liver cyt b5 and human liver cyt b5. The enzyme activities were found stable over limited cell passages with control values of 0.03 and 0.13 mumol/min/mg protein for NADPH and NADH cytochrome c (cyt c) reducing activity, 0.05 nmol cyt b5 and 0.013 nmol cytochrome P450 per milligram of microsomal protein. Phenobarbital/hydrocortisone showed a consistent, but not always significant increase in the NADPH and NADH cyt c reduction and benzanthracene an increase in the NADH cyt c reducing activity and cyt b5 content. Griseofulvin lowered the NADH cyt c reducing activity. Delta-aminolevulinic acid (0.5 mM) caused a significant decrease in the specific activity of all enzymes, as judged by a student's t test, with a p less than 0.001.
在结肠肿瘤细胞系LS174T中评估了培养变量对药物代谢系统各种酶的特定含量和活性的影响。这些细胞的NADH还原细胞色素b5（cyt b5）4光谱与大鼠肝细胞色素b5相似。当通过胰蛋白酶从膜上释放并浓缩后，发现cyt b5与兔抗大鼠肝细胞色素b5和人肝细胞色素b5抗体发生交叉反应。在有限的细胞传代过程中，酶活性保持稳定，NADPH和NADH细胞色素c（cyt c）还原活性的对照值分别为0.03和0.13 μmol/min/mg蛋白质，每毫克微粒体蛋白中含有0.05 nmol细胞色素b5和0.013 nmol细胞色素P450。苯巴比妥/氢化可的松使NADPH和NADH细胞色素c还原活性持续增加，但并非总是显著增加，苯并蒽使NADH细胞色素c还原活性和细胞色素b5含量增加。灰黄霉素降低了NADH细胞色素c还原活性。根据学生t检验，δ-氨基乙酰丙酸（0.5 mM）导致所有酶的比活性显著降低，p值小于0.001。
