Metal ion inactivation and chelator stimulation of Streptococcus mitis arginine aminopeptidase.

Activation of Streptococcus mitis (ATTC 9811) arginine aminopeptidase resulted in removal of the metal(s) from the enzyme molecule, and the action of the heavy metal ion in the inactivation process was shown to involve formation of a chelate complex between the enzyme molecule and metal or oxidation of functional group(s) on the enzyme surface. The enzyme also underwent activation by bovine serum albumin, amino acids, phosphate, and citric acid, which are probable physiological chelators.