Cardenas-Vazquez R, Yokosuka O, Billing B H
Biochem J. 1986 Jun 15;236(3):625-33. doi: 10.1042/bj2360625.
The presence of the enzyme bilirubin oxidase, which degrades bilirubin in vitro, was demonstrated in the liver. Subcellular-fractionation experiments indicate that bilirubin oxidase is located in both the inner and outer membranes of the mitochondria. The mean rate of the reaction is 1.57 +/- 0.38 (S.D.) nmol of bilirubin degraded/min per mg of mitochondrial protein (munits/mg of protein). With respect to the overall breakdown of bilirubin, the enzyme has a Km' of 136 microM-bilirubin and a Vmax.' of 9.13 munits/mg of protein. Its activity is influenced by the ionic strength of the media and is inhibited by KCN, thiol reagents, NADH and albumin. The enzyme is aerobic, and between 1 and 1.5 mol of O2 are consumed per mol of bilirubin degraded. The products of the reaction include propentdyopents. The hepatic bilirubin oxidase activity of the jaundiced Gunn-rat liver is not significantly different from that of the Sprague-Dawley rat, and it is not induced by beta-naphthoflavone.
在肝脏中证实存在可在体外降解胆红素的胆红素氧化酶。亚细胞分级分离实验表明，胆红素氧化酶定位于线粒体的内膜和外膜。反应的平均速率为每毫克线粒体蛋白每分钟降解1.57±0.38（标准差）纳摩尔胆红素（纳摩尔单位/毫克蛋白）。就胆红素的总体分解而言，该酶的米氏常数（Km'）为136微摩尔胆红素，最大反应速率（Vmax'）为9.13纳摩尔单位/毫克蛋白。其活性受介质离子强度的影响，并受到氰化钾、硫醇试剂、烟酰胺腺嘌呤二核苷酸（NADH）和白蛋白的抑制。该酶是需氧的，每降解1摩尔胆红素消耗1至1.5摩尔氧气。反应产物包括中胆绿素。黄疸型Gunn大鼠肝脏的肝胆红素氧化酶活性与斯普拉格-道利大鼠的无显著差异，且不受β-萘黄酮诱导。
