Transamination in pigeon breast muscle

Abstract

Transamination (Braunstein & Kritzmann) was studied in pigeon breast muscle. Of 21 different [alpha]-amino-acids studied in the presence of [alpha]-ketoglutaric acid, l([long dash]) aspartic acid and l(+) alanine were the most active in forming glutamic acid; dl-[alpha]-aminobutyric acid and l(+) valine were slightly active. The remaining amino-acids were not appreciably active. Of a series of ketonic acids tested, oxaloacetic and pyruvic acids showed the greatest activity in causing the anaerobic disappearance of glutamic acid; [alpha]-ketobutyric and mesoxalic acids were slightly active; [alpha]-ketovaleric, [alpha]-ketohexoic, acetoacetic and laevulic acids were not appreciably active. The data from these expts. could be explained by assuming the existence of 3 enzyme systems concerned with the following reactions Glutamic acid [image]ketoglutaric acid, aspartic acid [image] oxaloacetic acid, and alanine [image] pyruvic acid. By combination of these 3 systems the following reactions might be brought about: (1) [alpha]-Ketoglutaric acid + alanine [image] glutamic acid + pyruvic acid. (2) [alpha]-Ketoglutaric acid + aspartic acid [image] glutamic acid + oxaloacetic acid. (3) Oxaloacetic acid + alanine [image] aspartic acid + pyruvic acid. Transamination in pigeon breast muscle was inhibited by high concs. of cyanide. NaF, As2O3 and octyl alcohol had small inhibitory effects. Pyrophosphate, malonate, iodoacetate and bromo-acetate had no appreciable effect. Of a number of different amino compounds tested other than [alpha]-amino-acids, none was found to be active in transamination. Certain discrepancies between the results of Braunstein & Kritzmann [1938] and those reported here were discussed.