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