EVIDENCE FOR A TRICARBOXYLIC ACID CYCLE IN MYCOPLASMA HOMINIS

Abstract

VanDemark , P. J. (Cornell University, Ithaca, N.Y.), and P. F. Smith . Evidence for a tricarboxylic acid cycle in Mycoplasma hominis . J. Bacteriol. 88: 1602–1607. 1964.—Resting cells of acetate-grown Mycoplasma hominis strain 07 oxidized the various intermediates of the tricarboxylic and glyoxylate cycles, with the exception of sodium citrate and glyoxylate. Extracts of these cells possessed isocitric dehydrogenase, isocitratase, α-ketoglutaric dehydrogenase, succinic dehydrogenase, fumarase, malic dehydrogenase, citratase, and acetyl coenzyme A kinase activities. With the assay conditions employed, condensing enzyme, malate synthetase, and phosphotransacetylase activities were negligible. Incubation of sodium acetate- 2-C 14 with the various intermediates of the tricarboxylic acid cycle in the presence of cell-free extracts resulted in exchange of the isotope with these compounds as well as the formation of other labeled intermediates of the tricarboxylic acid cycle. Oxidation of sodium acetate- 2-C 14 alone resulted in the formation of labeled succinate, fumarate, and malate.