VERATRYL ALCOHOL OXIDASE ACTIVITY OF A CHEMICALLY-MODIFIED CELLULASE PROTEIN

A cellulase, cellobiohydrolase I (CBH I) from Trichoderma reesei was c hemically modified by covalent attachment of pentaammine ruthenium (II I) without loss in hydrolytic activity. Data suggest that such a modif ication endowed CBH I with oxidoreductase activity. The modified enzym e was able to carry out hydrogen peroxide-dependent oxidation of verat ryl alcohol, a substrate for lignin peroxidase, at a rate of 0.148 mu mol substrate oxidized min(-1) mu mol(-1) enzyme. The effects of pH, t emperature, and substrate concentration on the oxidation reaction were examined. The optimal temperature was determined to be 45 degrees C, and the optimal pH was 4.3. The K-m and V-max for veratryl alcohol wer e determined to be 3.519 mM and 52.27 mu M min(-1), respectively. Tart rate at concentrations as low as 0.10 mM was found to inhibit the reac tion. (C) 1994 Academic Press, Inc.