13 Arginine Kinase and Other Invertebrate Guanidino Kinases

Abstract

This chapter discusses arginine kinase and other invertebrate guanidino kinases. Arginine kinase was first found to be present in extracts of crab muscle and its presence was also demonstrated in octopus muscle. Two forms of arginine kinase have been isolated in homogeneous state from the muscle of L. polyphemus and shown to differ in their charges and stability, but not in their kinetic properties or molecular weights. The suggestion has been made that the isoenzymes are products of different genes. Indications have also been obtained for the presence of isoenzymes of arginine kinase in other invertebrate organisms. Arginine kinase is widely distributed among invertebrates and frequently occurs in association with creatine kinase. Some genera possess only a single guanidino kinase, while others contain up to three such enzymes. The Echinoidea are of special interest, in that their muscles contain both arginine and creatine kinases, while only arginine kinase is found in their unfertilized eggs and creatine kinase in their spermatozoa.