Mucor fragilis grown on bovine blood powder as the sole carbon source abundantly produced P-Nacetylhexosaminidase. The enzyme activity was several times higher than that of a culture obtained with glucose medium. The enzyme had two different molecular weight forms. The high-molecular-weight form had somewhat higher ,B-N-acetylgalactosaminidase activity than the lower-molecular-weight enzyme which had 13-N-acetylgalactosaminidase activity equivalent to about 40 % of its ,B-N-acetylglucosaminidase activity. Bovine blood seemed to induce both enzymes, but N-acetylamino sugars specifically induced the low-molecular-weight form. N-Acetylgalactosamine had an especially marked effect on activity. The low-molecular-weight form of enzyme was purified from the culture filtrate by fractionation with ammonium sulfate and various column chromatographies. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The optimum pH was 4.0 to 5.0 for P-N-acetylglucosaminidase activity and 5.5 to 6.5 for P-Nacetylgalactosaminidase activity. The enzyme hydrolyzed natural substrates such as diN -acetylchitobiose, tri-N-acetylchitotriose, and a glycopeptide obtained by modification of fetuin.

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