γ-Glutamyl transferase of swine kidney

Abstract

The enzyme of renal tissue responsible for the transfer of the γ-glutamyl grouping of glutathione to various acceptors was solubilized by a brief digestion with ficin and purified to apparent homogeneity by fractionation with ethanol and ammonium sulfate, chromatography on DEAE-cellulose, gel filtration with Sephadex, and gradient centrifugation. The enzyme was found to establish an equilibrium between products and reactants. Glutamic acid was not a product of the reaction and the enzyme was entirely without activity in the absence of an acceptor. The purified enzyme did not hydrolyze γ-glutamylnapthylamide and did not transfer the γ-glutamyl grouping of this compound to potential acceptors. An enzyme responsible for the hydrolysis of γ-glutamylnaphthylamide was separated from renal tissue and was found to be not influenced in its activity by the addition of acceptors. This enzyme was without activity in the hydrolysis of glutathione or of arylamide derivatives of other amino acids.