Bilirubin Dehydrogenase, an Enzyme in<i>Aspergillus ochraceus</i>IB-3 Useful for Diagnostic Measurement of Bilirubin
作者:Jun OGAWA、Woro Triarsi SULISTYANINGDYAH、Hiromi TANAKA、Kenji KANO、Tokuji IKEDA、Sakayu SHIMIZU
DOI:10.1271/bbb.66.2376
日期:2002.1
Bilirubin dehydrogenase, a membrane-bound enzyme that catalyzes the one-step oxidation of ditaurobilirubin and bilirubin to ditaurobiliverdin and biliverdin, respectively, in the presence of an electron acceptor, was found in Aspergillus ochraceus IB-3, and purified from the membrane fraction through solubilization by Triton X-100. Phenazine and quinone derivatives acted as electron acceptors. Accumulation of ditaurobiliverdin and biliverdin by enzyme catalysis increased the absorbance at 660 nm, which is far from the range of wavelengths affected by serum ingredients. The enzyme selectively oxidized ditaurobilirubin at low pH, so changes in the reaction pH enable the enzyme to discriminate between the bilirubin fractions ditaurobilirubin (an example of conjugated bilirubin) and bilirubin (an example of unconjugated bilirubin). Using the enzyme, 2 to 80 μM of ditaurobilirubin were measured accurately by monitoring the changes in absorbance at 660 nm.
在赭曲霉 IB-3 中发现了胆红素脱氢酶,它是一种膜结合酶,可在电子受体存在的情况下催化二去氧胆红素和胆红素一步氧化为二去氧胆红素和胆红素。吩嗪和醌衍生物是电子受体。在酶的催化作用下,二去氧胆红素和胆绿素的累积增加了 660 纳米波长处的吸光度,而这一波长远离受血清成分影响的波长范围。酶在低 pH 值时选择性地氧化二去氧胆红素,因此反应 pH 值的变化使酶能够区分胆红素组分二去氧胆红素(共轭胆红素的一个例子)和胆红素(未结合胆红素的一个例子)。使用该酶,通过监测 660 纳米波长处吸光度的变化,可准确测量 2 至 80 μM 的二靛基胆红素。