|
type |
Journal Article |
authors |
Wasserman, S. A.; Daub, E.; Grisafi, P.; Botstein, D.; Walsh, C. T. |
title |
Catabolic alanine racemase from Salmonella typhimurium: DNA sequence, enzyme purification, and characterization |
journal |
Biochemistry |
Activity |
5.1.1.1 |
Family |
5.1.1.1.a |
ui |
CarStse |
year |
(1984) |
volume |
23 |
number |
22 |
pages |
5182-7 |
| |
keywords |
Alanine Racemase/*genetics/isolation & purification |
abstract |
The alanine racemase encoded by the Salmonella typhimurium dadB gene was purified to 90% homogeneity from an overproducing strain. At 37 degrees C the enzyme has a specific activity of 1400 units/mg (V max, L- to D-alanine). Active enzyme molecules are monomers of Mr 39 000 with one molecule of pyridoxal 5'-phosphate bound per subunit. The Km's for L- and D-alanine are 8.2 and 2.1 mM, respectively. Measurement of turnover numbers yielded the expected Keq value of 1.0. Determination of 22 of the 25 N-terminal amino acid residues of the purified polypeptide allowed localization of cloned DNA encoding the structural gene. Sequencing of subcloned DNA revealed that the dadB gene encodes a polypeptide of 356 amino acids whose calculated molecular weight (apoenzyme) was 39 044. |
last changed |
2008/05/15 18:51 |
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