Kutty R K, Maines M D
Biochem Biophys Res Commun. 1984 Jul 18;122(1):40-6. doi: 10.1016/0006-291x(84)90436-4.
Treatment of rats with biliverdin (48 h) resulted in an increase in microsomal heme oxygenase activity in the liver. This was accompanied by decreases in the microsomal heme and cytochrome P-450 contents. In these respects cellular responses elicited by biliverdin resembled those produced by hematin (48 h). When rats were treated with biliverdin for a short interval (3 h) an inhibition of the activities of heme oxygenase and biliverdin reductase, concomitant with an increase in microsomal heme and cytochrome P-450 contents, were observed. Hematin was ineffective in altering these parameters under similar conditions. Biliverdin, in a concentration-dependent manner, inhibited the activities of purified heme oxygenase and biliverdin reductase. The activity of purified rat liver heme oxygenase was refractory to bilirubin, whereas that of purified biliverdin reductase was severely inhibited. It is suggested that biliverdin regulates cellular heme degradation processes by occupying the heme binding site on heme oxygenase, thus hindering the access of the substrate to the catalytic site of the enzyme.
用胆绿素处理大鼠（48小时）导致肝脏微粒体血红素加氧酶活性增加。这伴随着微粒体血红素和细胞色素P - 450含量的降低。在这些方面，胆绿素引发的细胞反应类似于高铁血红素（48小时）产生的反应。当用胆绿素短时间处理大鼠（3小时）时，观察到血红素加氧酶和胆绿素还原酶活性受到抑制，同时微粒体血红素和细胞色素P - 450含量增加。在类似条件下，高铁血红素在改变这些参数方面无效。胆绿素以浓度依赖的方式抑制纯化的血红素加氧酶和胆绿素还原酶的活性。纯化的大鼠肝脏血红素加氧酶的活性对胆红素不敏感，而纯化的胆绿素还原酶的活性则受到严重抑制。有人提出，胆绿素通过占据血红素加氧酶上的血红素结合位点来调节细胞血红素降解过程，从而阻碍底物进入酶的催化位点。
