NUCLEOSIDE OXIDASE, A HYDROGEN PEROXIDE-FORMING OXIDASE, FROM FLAVOBACTERIUM-MENINGOSEPTICUM

A novel enzyme which catalyzes the oxidation of nucleosides to nucleos ide-5'-carboxylic acids, forming hydrogen peroxide, was purified to ho mogeneity from Flavobacterium meningosepticum T-2799,The enzyme has a molecular weight of about 500,000, and four nonidentical subunits (mol ecular weights of 81,000, 69,000, 33,000, and 16,000) were detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On the bas is of visible absorption spectra of the purified enzyme, the enzyme is concluded to be a hemoprotein. It also contains covalently bound flav in adenine dinucleotide. The various nucleosides, such as adenosine (K -m = 48 mu M), inosine (K-m = 66 mu M), guanosine (K-m = 21 mu M), thy midine (K-m = 50 mu M), uridine (K-m = 80 mu M), and cytidine (K-m = 5 0 mu M), were oxidized by the enzyme, but nucleotides, bases, and ribo se were not.