L-LYSINE ALPHA-OXIDASE FROM TRICHODERMA-VIRIDE I4 - PURIFICATION AND CHARACTERIZATION

A L-lysine alpha-oxidase (LOD) has been purified to homogeneity in a t wo-step procedure with 300-fold enrichment and 60% recovery from the c ulture extract of Trichoderma viride i4. The enzyme catalyzes the reac tion between L-lysine and molecular oxygen forming 2-oxo-6-aminocaproa te, ammonia and hydrogen peroxide. Numerous substrates have been teste d. The K-m value for L-lysine was found to be 0.026 mM. Its apparent m olecular mass is 110000 Da when determined by gel filtration on Sephad ex G-200, the estimated molecular weight of the subunits being 55000 D a in the SDS-PAGE. The enzyme is a glycoprotein and shows absorption m axima at 276, 386 and 463 nm. It was found to contain 1 mol of FAD per subunit. The coenzyme is bound non-covalently. Its isoelectric point is at pH 4.3. The enzyme is stable at extreme pH values, at relatively high temperatures and in diluted hydrogen peroxide. The enzyme descri bed here differs from two other known L-lysine oxidases previously cha racterized with regard to its amino acid composition and its substrate specificity.