title: Purification and properties of aromatic amino acid aminotransferases from Azospirillum brasilense UAP 14 strain.
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.
authors.affiliation: Centro de Investigaciones Microbiológicas, Universidad Autónoma, de Puebla, México.
authors.forename: L
authors.initials: L
authors.lastname: Soto-Urzua
authors.forename: Y G
authors.initials: YG
authors.lastname: Xochinua-Corona
authors.forename: M
authors.initials: M
authors.lastname: Flores-Encarnacion
authors.forename: B E
authors.initials: BE
authors.lastname: Baca
mesh_terms: D015806:Azospirillum brasilense / Q000201:enzymology*; D000637:Transaminases / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000637:Transaminases; C019729:aromatic amino acid aminotransferase