Isolation and characterization of argininosuccinate synthetase from human liver

Abstract

This communication describes the purification and characterization of argininosuccinate synthetase from human liver. By numerous criteria including electrophoresis in sodium dodecyl sulfate-containing gels, electrophoresis in nondissociating gels and analytical ultracentrifugation, the protein is homogeneous at a specific activity of 4.2 .mu.mol/(min mg) assayed at 37.degree. C in the direction of argininosuccinate synthesis. The enzyme has a MW of 183,000, as determined by gel filtration. Electrophoresis in the presence of sodium dodecyl sulfate yielded a single band migrating with an Rf corresponding to 43,000 daltons. The enzyme may contain 4 subunits of identical MW. The S20,w of the enzyme is 8.2 S. Antibodies were prepared in rabbits directed against the purified protein. These antibodies react specifically with argininosuccinate synthetase, as determined by electrophoretic analysis of the immunoadsorbed product from crude extracts of human liver. The human enzyme has very similar properties to those published for the beef and rat liver enzymes.