1. The rate of hydrolysis at different pH values of glycyl glycine, glycyl leucine, glycyl alanine, glycyl asparagine, glycyl aspartic acid and biuret base has been determined. 2. The pH-activity curves obtained in this way differ for the different substrates. 3. The curves can be satisfactorily predicted by the assumption that erepsin is a weak acid or base with a dissociation constant of 10(-...

Equilibrium constants have been measured potentiometrically for the mixed-ligand complexes, copper (U)-amines (A)-dipeptides (L). The aromatic amines (A) used are 5-nitro-l,lO-phenanthroline (Nphen), 2,2'-pyridyl benzimidazoline (pybz), 1,lO-phenanthroline (phen) and 2,2'-pyridyl imidazoline (pyz). The dipeptides used are glycylglycine (gg), glycyl-l-alanine (ga) and glyeyl-l-Ieucine (gl), The ...

Quinaldic acid, which was found to be a metabolite of kynurenic acid (l), was not conjugated by the rabbit (2), but was excreted by the rat both free and as the glycine conjugate (3). When quinaldic acid was administered orally or parenterally to the cat, the urine contained little, if any, quinaldic acid or quinaldylglycine, but about two-thirds of the compound was accounted for as quinaldylgl...

1 . The intestinal absorption of carnosine, glycylglycine, glycyl-D-phenylalanine, glycyl-L-phenylalanine, glycyl-L-proline and L-prolylglycine were investigated after intraluminal injection of dipeptide into anaesthetized rats. 2. With all six dipeptides, the intact substance was detected by ion-exchange chromatography in blood samples taken from the superior mesenteric vein. 3. The rate of hy...

The enzyme γ-glutamyltransferase (GGT) catalyzes the hydrolysis of the γ-glutamyl isopeptide bond of glutathione conjugates (donor substrates), releasing glutamic acid, or the transfer of the donor's γ-glutamyl group to an acceptor substrate, such as a dipeptide. The specificity of GGT for xenobiotic donor substrates has not been fully characterized. The transpeptidation activity of bovine kidn...