THE EFFECT OF METAL IONS ON ARGINASE FROM THE ZEBRA MUSSEL DREISSENA POLYMORPHA

摘要

Arginase (L-arginine amidinohydrolase, Ec 3.5.3.1) is widely distributed in living organisms. The effect of metal ions on arginase was studied in the zebra mussel, a new exotic species of mollusk that was recently introduced into the Great Lakes. Arginase activity as found in both soluble and membrane-bound forms in the zebra mussel. Like all other arginases. zebra mussel arginase required Mn2+ for activity. In addition to Mn2+, arginase was also activated by Ni2+ and Co2+. The activation by Ni2+ was time dependent, unlike the activation by Mn2+ and Co2+. Several bivalent and trivalent metal ions were inhibitors of the enzyme. Dialysis of the soluble arginase with or without prior activation by Mn2+ caused a large loss in enzyme activity which could not be recovered by incubation with Mn2+, Ni2+, or Co2+. Arginase was inhibited by high concentrations of substrate, and the K-m of the enzyme was similar with or without Mn2+, Ni2+, or Co2+. (C) 1997 Elsevier Science Inc. [References: 29]