title: Bilirubin dehydrogenase, an enzyme in Aspergillus ochraceus IB-3 useful for diagnostic measurement of bilirubin.
abstract: 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 microM of ditaurobilirubin were measured accurately by monitoring the changes in absorbance at 660 nm.
authors.affiliation: Division of Applied Life Sciences, Laboratory of Fermentation Physiology and Applied Microbiology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ogawa
authors.forename: Woro Triarsi
authors.initials: WT
authors.lastname: Sulistyaningdyah
authors.forename: Hiromi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Kano
authors.forename: Tokuji
authors.initials: T
authors.lastname: Ikeda
authors.forename: Sakayu
authors.initials: S
authors.lastname: Shimizu
mesh_terms: D001235:Aspergillus ochraceus / Q000145:classification / Q000201:enzymology*; D016227:Benzoquinones / Q000737:chemistry / Q000494:pharmacology; D001663:Bilirubin / Q000031:analogs & derivatives* / Q000032:analysis* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D008773:Methylphenazonium Methosulfate / Q000031:analogs & derivatives / Q000494:pharmacology; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000187:drug effects / Q000378:metabolism*; D013053:Spectrophotometry / Q000379:methods; D013379:Substrate Specificity; D013654:Taurine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
chemical_list: D016227:Benzoquinones; D013654:Taurine; D008773:Methylphenazonium Methosulfate; C046673:ditaurobilirubin; D010088:Oxidoreductases; D001663:Bilirubin