Asparagine transaminase from rat liver.
Asparagine transaminase has been purified about 200-fold from rat liver. The enzyme has a broad specificity toward both amino acids and alpha-keto acids. Thus, amino acids substituted in the beta position such as asparagine, S-methylcysteine, phenylalanine, cysteine, serine, and aspartate are substrates. The enzyme is also active with alanine, methionine, homoserine, alpha-aminobutyrate, glutamine, and leucine. The enzyme has a high affinity for glyoxylate but the affinity falls off markedly through the series glyoxylate, pyruvate, alpha-ketoburyrate, alpha-Keto acids substituted in the beta or gamma position, such as alpha-ketosuccinamate, phenylpyruvate, p-hydroxyphenylpyruvate, alpha-keto-gamma-methiolburyrate, and alpha-keto-gamma-hydroxybutyrate, are substrates for the enzyme. Amino acids or alpha-keto acids possessing a branch point at the beta carbon are inactive. Kinetic analysis of the asparagine glyoxylate transamination reaction is consistent with a ping-pong mechanism.
D000596:Amino Acids; D000818:Animals; D001216:Asparagine; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D051381:Rats; D013329:Structure-Activity Relationship; D000637:Transaminases / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D001216:Asparagine; D000637:Transaminases; C019741:asparagine-oxo-acid aminotransferase