Purification and properties of alpha-D-mannosidase from the limpet, Patella vulgata.
1. alpha-Mannosidase from the limpet, Patella vulgata, was purified nearly 150-fold, with 40% recovery. beta-N-Acetylglucosaminidase was removed from the preparation by treatment with ethanol. The final product was virtually free from beta-galactosidase. 2. Limpet alpha-mannosidase was assayed at pH3.5 and at this pH it was necessary to add Zn(2+) for full activity. At pH5, the enzyme had the same activity in the presence or absence of added Zn(2+). 3. On incubation at acid pH, the enzyme underwent reversible inactivation, which was prevented by adding Zn(2+). 4. EDTA accelerated inactivation and the addition of Zn(2+) at once restored activity. No other cation was found to reactivate the enzyme. 5. Cl(-) had an unspecific effect on hydrolysis by limpet alpha-mannosidase. It increased the rate of reaction with substrate. The anion did not prevent or reverse inactivation by EDTA. 6. It is concluded that alpha-mannosidase is a metalloenzyme or enzyme-metal ion complex, dissociable at the pH of activity, and that it requires Zn(2+) specifically.
D000818:Animals; D002712:Chlorides; D004492:Edetic Acid; D004789:Enzyme Activation; D006026:Glycoside Hydrolases / Q000032:analysis / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008974:Mollusca; D015032:Zinc
D002712:Chlorides; D004492:Edetic Acid; D006026:Glycoside Hydrolases; D015032:Zinc