β-N-Acetylhexosaminidase (EC 3.2.1.52) from the culture filtrate of Nocardia orientalis was purified to homogeneity by precipitation with ammonium sulfate followed by column chromatography on CM-Sephadex, Bio-Gel P-60, and phenyl-Sepharose CL-4B. The molecular weight of the enzyme was about 56, 000 by gel filtration and 54, 000 by SDS polyacrylamide gel electrophoresis. The enzyme showed about 1.6-fold higher β-N-acetylglucosaminidase activity than β-N-acetylgalactosaminidase activity. The optimum pH and temperature were 5.0 and around 70-75°C for PNP-GlcNAc, and 4.0 and 60°C for PNP-GalNAc. The enzyme was stable in the pH range from 4.0 to 8.0 and below 45°C. The enzyme hydrolyzed N-acetyl-chitooligosaccharides, di-N-acetyl-chitobiose through hexa-N-acetyl-chitohexaose. The enzyme showed glycosyl transferase activity during the hydrolysis of di-N-acetyl-cnitobiose. Two major transfer products were isolated and identified as the β(1→6)-linked disaccharide of N-acetylglucosamine and tri-N-acetyl-chitotriose.

This article cannot obtain the latest cited-by information.