Crystallization and properties of L-lactate oxidase from Mycobacterium smegmatis.

1. An original method was devised for purifying and crystallizing l-lactate oxidase from Mycobacterium smegmatis. 2. The crystalline enzyme exhibited a single protein component (S(0) (20,w) 14.7s) in the ultracentrifuge and also on electrophoresis on cellulose acetate strips. 3. The enzyme has a typical flavoprotein spectrum, and it was confirmed that the prosthetic group is FMN. 4. Preliminary studies indicated that the molecular weight is in the range 300000-400000. Since the minimum molecular weight was found to be 50000+/-3000, it was concluded that l-lactate oxidase contains 6-8moles of flavine/mole. 5. Other properties of the enzyme reported include the substrate specificity, an apparent K(m) for l-lactate, the effect of several inhibitors on the enzyme activity and the pH-activity curve.