Catalyzes the hydrolysis of the amide bond in N-(4-oxoglutarate)-L-cysteinylglycine (deaminated glutathione), a metabolite repair reaction to dispose of the harmful deaminated glutathione. H2O + N-(4-oxoglutaryl)-L-cysteinylglycine = 2-oxoglutarate + L-cysteinylglycine Belongs to the carbon-nitrogen hydrolase superfamily. NIT1/NIT2 family. The gene for this protein is duplicated in strains AX3 and AX4. These strains contain a duplication of a segment of 750 kb of chromosome 2 compared to the corresponding sequence in strain AX2.