抄録
A new enzyme, N-acyl-D-hexosamine oxidase, was purified to homogeneity on polyacrylamide gel electrophoresis from Pseudomonas sp. 15-1 by successive procedures involving CM-cellulose fractionation and chromatographies on Phenyl-Sepharose, QAE-Sephadex, SE-Sephadex, and Sephadex G-200, and some properties were investigated. Its molecular weight was 170, 000 on gel filtration and it was composed of one each of four non-identical subunits; 63, 000, 44, 000, 36, 000, and 22, 000. The absorption spectrum of the enzyme was the same as those of many flavoproteins. Its isoelectric point was at 7.9. Characteristically, the enzyme showed its activity throughout a wide pH range and the optimum pH was 8.0. N-Acetyl- and N-glycolyl-D-glucosamine and N-acetyl-D-galactosamine were oxidized as good substrates of the enzyme and their apparent Km were 0.24, 2.6 and 0.10 mM, respectively. But N-acetyl-D-mannosainine was a poor substrate. The anomeric configuration of the substrate required was β-form. The reaction products from 1 mol each of N-acetyl-D-glucosamine and oxygen were found to be 1 mol each of N-acetyl-D-glucosaminic acid and hydrogen peroxide. The enzyme was inhibited specifically by Zn2+. A preliminary study suggested that the enzyme might be useful for measurement of N-acetyl-β-D-glucosaminidase.
