Purification and some properties of bilirubin oxidase of Myrothecium verrucaria MT-1.

Abstract

Bilirubin oxidase was purified from the culture filtrate of Myrothecium verrucaria MT-1 by a procedure involving ammonium sulfate precipitation, charcoal treatment, and QAE-Sephadex A50 and Sephadex G-100 column chromatographies. The purified enzyme was homogeneous on disc gel electrophoresis. Copper and carbohydrate were contained in the enzyme. The enzyme was inhibited by Fe2+ and compounds that complex with copper. Bilirubin, biliverdin, hemin and chlorophyllin which consist of tetrapyrrole, and substrates of laccase were oxidized by the enzyme. Bilirubin was oxidized more rapidly than other substances. Bilirubin oxidase differed from laccase in reactivity with substances consisting of tetrapyrrole. Substances consisting of tetrapyrrole were oxidized only a little by laccase but rapidly oxidized by bilirubin oxidase. The apparent Km value for bilirubin was calculated to be 190μM.