Human α‐N‐Acetylglucosaminidase

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Abstract
α‐N‐Acetylglucosaminidase was purified from human urine to a state of apparent homogeneity. α‐N‐Acetylglucosaminidase is a glycoprotein with an extensive charge heterogeneity. The molecular weight determined by gel filtation is 307 000. Polyacrylamide gel electrophoresis in the absence and presence of sodium dodecyl sulfate indicates molecular weight heterogeneity of isocharged forms of the purified enzyme. The enzyme has a pH optimum of 4.5 ± 0.3 and Km and V values of 0.14–0.74 mM, and 1.04–3.68 μmol mg−1 min−1 for three ary1 2‐acetamido‐2‐deoxy‐α‐D‐glucosides and UDP‐N‐acetylglucosamine. Heparan sulfate, heparin and dermatan sulfate are competitive inhibitors. The enzyme is inhibited by Hg2+ and Cu2+. ‐SH‐protective reagents and thiol reagents have no effect on the enzyme activity. Heating at 65°C and pH values below 5 inactivate the enzyme rapidly.