1.
Can J Microbiol
; 42(3): 294-8, 1996 Mar.
Article
in English
| MEDLINE
| ID: mdl-8868238
ABSTRACT
The purification and characterization of AAT1, one of two aromatic amino acid aminotransferase (EC 2.6.1.57) in Azospirillum brasilense, is described. Purified AAT1 had a subunit mass of 33 kDa and a nondenatured molecular mass of 66 kDa, suggesting a dimeric structure. Other properties include a pI of 5.04, an optimum temperature of 45 degrees C, and optimum pH of 8.5. AAT1 utilized all aromatic amino acids, the L-tryptophan derivatives such as L-5-methyl tryptophan and L-flour-tryptophan, and L-histidine. The apparent Km values for L-tyrosine, L-phenylalanine, and L-tryptophan were 0.19, 0.43, and 1.05 mM, respectively. The enzyme was competive inhibited by indole-3-pyruvic acid with a Ki of 0.17 mM.