Purification of an enzyme responsible for acetate formation from acetyl coenzyme A in Selenomonas ruminatium

Abstract

An enzyme, capable of catalyzing the ADP-dependent conversion of acetyl coenzyme A, propionyl coenzyme A and succinyl coenzyme A into the corresponding free acids, has been purified from the strict rumen anaerobe Selenomonas ruminantium. All three activities cochromatographed and have been purified 60-fold. As determined by gel filtration, the molecular weight of this enzyme was 230 000. Gel electrophoresis in native gels resolved the purified protein fraction into a major and three minor protein bands. The relative mobility of the major band coincided with the relative mobility of single bands that were obtained when gels were stained for activity with each of the three substrates. The physiological role of this new enzyme is discussed.