PURIFICATION AND PROPERTIES OF BILIRUBIN OXIDASE FROM MYROTHECIUM-VERRUCARIA

Bilirubin oxidase was purified from a culture filtrate of Myrothecium verrucaria Mv 2,1089 by DEAE-cellulose and Sephadex G-100 column chromatographies. The purified enzyme had a specific activity of 30 U/mg protein and showed a single band on polyacrylamide gel electrophoresis. Some of the general properties of this bilirubin oxidase were as follows: the optimum pH for the enzyme reaction was 7.5 and the optimum temperature was 50-degrees-C. The enzyme was stable at pH ranging from 9.0 to 9.5. The mol wt was calculated to be 61,900-62,700 by SDS-PAGE and gel-filtration technique. The apparent K(m) value of the bilirubin oxidase was calculated to be 9.4 x 10(-5) mol/L. The enzyme activity was greatly reduced by incubation of bilirubin oxidase with Fe2+, Hg+, NaN3, NH4+, and Zn2+. The enzyme reaction was inhibited in the presence of Ca2+, Hg+, Zn2+, Fe2+, and BSA.