PROPERTIES OF ASCORBATE OXIDASE PRODUCED BY ACREMONIUM SP HI-25

The presence of copper and carbohydrate was demonstrated in an acidic ascorbate oxidase purified from Acremonium sp, HI-25, The enzyme was i nhibited by cyanide, azide, and sulfide, The reaction product from L-a scorbic acid was identified to be dehydro-L-ascorbic acid. This enzyme did not oxidize other electron donors than ascorbate derivatives, Sto ichiometric investigations on the oxidation reaction found that this e nzyme belongs to the EC 1.10.3.3 group, using molecular oxygen as an e lectron acceptor, The K-m for L-ascorbic acid was estimated to be 0.29 mM, The activation energy for inactivation of Acremonium ascorbate ox idase, 129 kcal/mol, was four and three times higher than those of asc orbate oxidases from cucumber and pumpkin, respectively.