Further characterization of L-leucine-pyruvate transaminase from Acetobacter suboxydans

L-Leucine-pyruvate transaminase obtained from Acetobacter suboxydans exhibited absorbance maxima to 280 and 332 nm. The 332 nm peak was derived from the coenzyme bound to the enzyme protein with the epsilon NH2 of a lysine residue. The transaminase showed reactivity against many L-amino acids. The relation between the reactivity and the structure of the amino donor is discussed. The Michaelis constants for L-leucine, pyruvate, L-alanine and alpha-ketoisocaproate were 6.7, 3.1, 7.1 and 0.9 mM, respectively. The equilibrium constant was 5.3. The activation energy at pH 5.0 was 8,800 cal/mol.