|
type |
Journal Article |
authors |
Yonaha, K.; Suzuki, K.; Toyama, S. |
title |
Streptomyces beta-alanine:alpha-ketoglutarate aminotransferase, a novel omega-amino acid transaminase. Purification, crystallization, and enzymologic properties |
journal |
J Biol Chem |
Activity |
2.6.1.19 |
ui |
85131114 |
year |
(1985) |
volume |
260 |
number |
6 |
pages |
3265-8. |
| |
keywords |
4-Aminobutyrate Transaminase/*isolation & purification |
abstract |
An enzyme which catalyzes the transamination of beta-alanine with alpha- ketoglutarate was purified to homogeneity from Streptomyces griseus IFO 3102 and crystallized. Molecular weight of the enzyme was found to be 185,000 +/- 10,000 by a gel-filtration method. The enzyme consists of four subunits identical in molecular weight (51,000 +/- 1,000). The transaminase is composed of 483 amino acids/subunit containing 7 and 8 residues of half-cystine and methionine, respectively. The enzyme exhibits absorption maxima at 278 and 415 nm. The pyridoxal 5'- phosphate content was determined to be 4 mol/mol of enzyme. The enzyme catalyzes transamination of omega-amino acids including taurine and hypotaurine. beta-Alanine and DL-beta-aminoisobutyrate served as a good amino donor; the Michaelis constants are 8.0 and 12.5 mM, respectively. alpha-Ketoglutarate is the only amino acceptor (Km = 4.0 mM); pyruvate and oxalacetate are inactive. Based on the substrate specificity, the terminology of beta-alanine:alpha-ketoglutarate transaminase is proposed for the enzyme. Carbonyl reagents, HgCl2,DL-gabaculine, and alpha-fluoro-beta-alanine strongly inhibited the enzyme. |
last changed |
2002/11/04 17:41 |
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