PURIFICATION AND PROPERTIES OF L-ALANINE DEHYDROGENASE FROM VEGETATIVE CELLS OF BACILLUS CEREUS

Abstract

McCormick, Neil G. (University of Wisconsin, Madison), and Harlyn O. Halvorson. Purification and properties of l-alanine dehydrogenase from vegetative cells of Bacillus cereus. J. Bacteriol. 87:68-74. 1964.-The l-alanine dehydrogenase from vegetative cells of Bacillus cereus strain T has been purified approximately 200-fold. The enzyme has a molecular weight of 248,000 and a turnover number of 80,000 moles of substrate per min per mole of enzyme. The Michaelis constants for the substrates and the equilibrium constant for the reaction catalyzed by this enzyme are in close agreement with reported values for other l-alanine dehydrogenases. The kinetic properties of the enzyme purified from vegetative cells are identical to those of the enzyme isolated from spores of the same organism, but differ with respect to relative heat stability. Whereas spores contain a heat-resistant enzyme, vegetative cells contain, in addition, a heat-sensitive enzyme. No evidence was found to support the hypothesis that a molecular conversion type of phenomenon plays a role in the appearance of spore enzyme.