PARTIAL-PURIFICATION AND CHARACTERIZATION OF GLYOXYLATE OXIDASE FROM THE BROWN-ROT BASIDIOMYCETE TYROMYCES-PALUSTRIS

The glyoxylate oxidase which catalyses oxidation of glyoxylate to form oxalate and H2O2 was partially purified from the homogenate of a wood-destroying basidiomycete Tyromyces palustris by a combination of (NH4)(2)SO4 precipitation, DEAE-Biogel chromatography and Sephadex G-100 gel filtration. The enzyme purification factor was 60 with 58% recovery. The partially purified enzyme exhibited the pH optimum at about 8. Among the compounds tested, the best substrate was glyoxylate. Glycollate and glycolaldehyde were slightly utilized, but none of the others, such as glyoxal, formaldehyde, acetaldehyde, formate, oxalate, or L-malate was effective. The K-m value for glyoxylate was determined to be 3.7 mM. Enzymatic oxidation was competitively inhibited by oxalate; the K-i value for oxalate was 50 mu M. p-Chloromercuribenzoate and benzoquinone also strongly inhibited the enzyme. 2,6-Dichloroindophenol and potassium ferricyanide served as electron accepters but neither NAD nor NADP was effective. Neither FMN nor FAD enhanced the enzyme activity. The M, of the purified enzyme was estimated to be ca 127 000 on Sephadex G-100 gel filtration.