PURIFICATION AND PROPERTIES OF ENZYMES INVOLVED IN THE PROPIONIC ACID FERMENTATION

Allen , S. H. G. (Western Reserve University, Cleveland, Ohio), R. W. Kellermeyer, R. L. Stjernholm, and Harland G. Wood . Purification and properties of enzymes involved in the propionic acid fermentation. J. Bacteriol. 87: 171–187. 1964.—Chromatographic procedures are described for the separation and purification of phosphotransacetylase, acetyl kinase, malic dehydrogenase and coenzyme A (CoA) transferase. Purity of the enzymes was judged by homogeneity in an ultracentrifuge and by specific activity. Phosphotransacetylase was obtained 85% pure with a specific activity of 27.1. The preparation of acetyl kinase was a homogeneous protein with a specific activity of 531. The malic dehydrogenase likewise was homogeneous with a specific activity of 938. The CoA transferase, which was about 56% pure with a specific activity of 42.6, is the purest preparation of this enzyme yet described. The pH optimum was 6.5 to 7.8, and the K m for succinyl-CoA in the transfer of CoA to acetate was found to be 1.3 × 10 −4 m ; for acetate, in the same transfer, the K m was 7.0 × 10 −3 m ; for succinyl-CoA to propionate it was 6.8 × 10 −5 m , and for propionate, in the same reaction, 6.2 × 10 −4 m . Methods are described for the enzymatic production of methyl-malonyl-CoA, malonyl-CoA, propionyl-CoA, acetyl-CoA, and succinyl-CoA. The role of these enzymes in the propionic acid fermentation as well as the possible mechanism responsible for the high yields of adenosine triphosphate from glucose are considered.