Isolation and properties of gamma-glutamyltranspeptidase from Morris hepatoma 5123D.

gamma-Glutamyltranspeptidase was purified 600-fold from Morris hepatoma 5123D by six-step procedure. Its apparent molecular weight estimated by centrifugation in sucrose gradient with Triton X-100 amounts to 108 000. Some dipeptides particularly glycylglycine and several amino acids considerably increase the enzyme activity but L-serine with borate decreases it. Usually transfer activity of the enzyme towards gamma-L-glutamyl substrates was much higher than hydrolytic. The best substrate for the hepatoma enzyme is reduced glutathione.