Characterization and distribution of arginine kinase in the tissues of the scorpion, Palamneus phipsoni

Abstract

Arginine kinase in claw muscle extracts of the scorpion, Palamneus phipsoni, was characterized. The enzyme, with a pH optimum of 8.5 in the direction of phosphoarginine synthesis, showed activation by Mg2+, high specificity towards L-arginine as the guanidino substrate, slight inhibition by high concentrations of L-arginine and ATP, and a molecular weight of 33 500. On polyacrylamide gel electrophoresis at pH 8.3 the enzyme migrated to the anode as a single molecular species. In addition to the claw muscle, the enzyme activity was also found to be present in the heart, alimentary canal, hepatopancreas, and nervous system. In general, scorpion muscle arginine kinase appears to be similar in its properties to the enzyme from other arthropods.