This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lim, Y H Articles by Soda, K Search for Related Content PubMed PubMed Citation Articles by Lim, Y H Articles by Soda, K

 Previous Article  |  Next Article 

J Bacteriol. 1993 July; 175(13): 4213-4217

research-article

A new amino acid racemase with threonine alpha-epimerase activity from Pseudomonas putida: purification and characterization.

Institute for Chemical Research, Kyoto University, Japan.

ABSTRACT

We have found that Pseudomonas putida ATCC 17642 cells grown in a medium containing D-threonine as the sole nitrogen source produce an enzyme that catalyzes epimerization of threonine. Proton nuclear magnetic resonance analysis of the enzyme reaction in deuterium oxide clearly showed epimerization from L- to D-allo-threonine and also from D- to L-allo-threonine. This is the first example of an enzyme that was clearly shown to epimerize threonine. The enzyme has been purified to homogeneity, which was shown by polyacrylamide gel electrophoresis. The enzyme has a molecular weight of about 82,000 and consists of two subunits identical in molecular weight (about 41,000). The enzyme contains 1 mol of pyridoxal 5'-phosphate per mol of subunit as a cofactor, and its absorption spectrum exhibits absorption maxima at 280 and 420 nm. The enzyme catalyzes not only epimerization of threonine by stereoconversion at the alpha position but also racemization of various amino acids, except acidic and aromatic amino acids. The enzyme is similar to amino acid racemase with low substrate specificity (EC 5.1.1.10) in enzymological properties but is distinct from it in the action on threonine.

This article has been cited by other articles:

• Chen, H.-P., Lin, C.-F., Lee, Y.-J., Tsay, S.-S., Wu, S.-H. (2000). Purification and Properties of Ornithine Racemase from Clostridium sticklandii. J. Bacteriol. 182: 2052-2054 [Abstract] [Full Text]  
• Guenzi, E., Galli, G., Grgurina, I., Gross, D. C., Grandi, G. (1998). Characterization of the Syringomycin Synthetase Gene Cluster. A LINK BETWEEN PROKARYOTIC AND EUKARYOTIC PEPTIDE SYNTHETASES. J. Biol. Chem. 273: 32857-32863 [Abstract] [Full Text]  
• Lim, Y. H., Yoshimura, T., Kurokawa, Y., Esaki, N., Soda, K. (1998). Nonstereospecific Transamination Catalyzed by Pyridoxal Phosphate-dependent Amino Acid Racemases of Broad Substrate Specificity. J. Biol. Chem. 273: 4001-4005 [Abstract] [Full Text]  
• Park, I.-S., Lin, C.-H., Walsh, C. T. (1997). Bacterial resistance to vancomycin: Overproduction, purification, and characterization of VanC2 from Enterococcus casseliflavus as a D-Ala-D-Ser ligase. Proc. Natl. Acad. Sci. USA 94: 10040-10044 [Abstract] [Full Text]