ω-Amino acid-pyruvate aminotransferase

Abstract

Succinic semialdehyde -FL-Glutamate 13-alanine transaminase is characterized by its requirement for pyruvate and r-aminobutyrate transaminase for a-ketoglutarate as an amino acceptor. With the latter enzyme, many studies have been carried out using mammalian enzyme with an emphasis on its physiological function.8-10) Some of them were purified to homogeneity and partially characterized. There are another (0-amino acid transaminase catalyzing transamination of co-amino group of a, w-diaminocarboxylic acid such as C6 of L-lysine and C5 of L-ornithine, which were purified and crystallized from bacteria. These enzymes, however, do not catalyze the transamination of r-aminobutyrate or p-alanine. Taurine : a-ketoglutarate aminotransferase catalyzing transamination of (0-amino acids besides that of taurine was also purified and crystallized from Achromobacter superficialis.13) Recently, we purified and crystallized co-amino acid: pyruvate and r-aminobutyrate : a-ketoglutarate aminotransferase from Pseudomonas sp. F-126, which enabled us to characterize the enzymologic properties in detail.14-18) In this review we will try briefly to present and discuss some properties of the (0-amino acid transaminase in comparison with other transaminases, especially r-aminobutyrate transaminase.co-Amino acid : pyruvate aminotransferase designated previously taurine : pyruvate aminotransferase14) can be classified as p-alanine : pyruvate aminotransferase (E.C. 2.6.1.18). The terminology, however, of "w-amino acid: pyruvate aminotransferase" is more relevant from the view point of its substrate specificity as described below.

Features and technical applications of ω-transaminases

“…When an w-TA capable of deaminating (S)-α-methylbenzylamine ((S)-α-MBA) was first reported as a research paper (Shin and Kim 1997), the 5-TA was expected to be a variant of 5-amino acid:pyruvate transaminase (5-APT) (EC 2.6.1.18) because 5-APT was the only 5-TA at that time that was known to deaminate amine compounds (Yonaha et al 1987). However, it turned out that the newly found 5-TA was very different from 5-APT, because the 5-TA could not deaminate β-alanine which is a typical amino donor of 5-APT (Shin and Kim 2002).…”

ω-Amino Acid:Pyruvate Transaminase from Alcaligenes denitrificans Y2k-2: a New Catalyst for Kinetic Resolution of β-Amino Acids and Amines

“…To prepare the crude extract, the harvested cells (10 g of cell wet weight) of A. denitrificans Y2k-2 were suspended in 20 ml of sonication buffer, which contains 20 M PLP, 0.2 mM EDTA, 1.0 mM phenylmethylsulfonyl fluoride (PMSF), and 0.01% (wt/wt) 2-mercaptoethanol in 10 mM phosphate buffer (pH 7.0), and disrupted by sonication at 4°C. It was strongly inhibited by 5 mM 3-amino-2,3-dihydrobenzoic acid (gabaculine), hydroxylamine, or aminooxyacetic acid (25), and equivalent amounts of L-alanine were produced according to the consumed pyruvate. The enzyme involved in the kinetic resolution was confirmed to be an -amino acid:pyruvate transaminase (-APT).…”

“…However, none of these proteins has been biochemically characterized yet. AptA had 45% identity to -APT from Pseudomonas putida, which is the only well-characterized enzyme (25,26). The linear alignment of AptA and the six related proteins mentioned above showed that these enzymes are highly homologous to each other (Fig.…”

Use of Enrichment Culture for Directed Evolution of the Vibrio fluvialis JS17 ω-Transaminase, Which Is Resistant to Product Inhibition by Aliphatic Ketones

“…Among the TAs, only -TA has been reported to show catalytic activity towards primary amines (6,21). Therefore, the chemical properties of the starting amino donor and acceptor substrates in the -TA reaction are often different from those of the resulting products.…”

“…TAs can be classified as ␣-or -TA according to the position of the amino group transferred with respect to the carboxyl group of the substrate (8,9,21). Among the TAs, only -TA has been reported to show catalytic activity towards primary amines (6,21).…”