EFFECT OF CERTAIN CATIONS ON ACTIVITY OF LEUCINE NAPHTHYLAMIDASES OF PARAMECIUM CAUDATUM

Abstract

Spectrophotometric methods were used to study the activity of the leucine naphthylamidases of Paramecium caudatum. Optimum activity of the enzymes occurred from pH 6.6 to 6.8 and was enhanced by either Co2+, Mn2+, or by Mg2+. Maximum activity occurred when Co2+ was used with either Mg2+ or Mn2+. Activity was depressed by either Sr2+, Fe2+, Zn2+, Ni2+, Hg2+, Cd2+, Pb2+, Sn2+, or Li2+, and not affected by Ba2+, Cu2+, and Ca2+. Approximately 40% of the enzymatic activity was inhibited by EDTA. Most of this inhibition was reversed by either Mg2+, Co2+, or Mn2+.