Acetyl coenzyme A and coenzyme A contents of growing Clostridium kluyveri as determined by isotope assays

Abstract

CoASH and some of its acyl derivatives, especially acetyl-SCoA, occupy a central position in the energy metabolism of the anaerobic Clostridium kluyveri, both as intermediates and as regulatory effectors. The steady state concentrations of these compounds were determined in growing cultures of this organism using an anaerobic and fast deproteinization technique and radio isotope assays. Acetyl-SCoA was determined as [1-14C]citrate formed in the presence of [4-14C]oxaloacetate and citrate synthase; 0.49 mumol/g cell wet wt. were found. CoASH, CoAS-SCoA after borohydride reduction, and total acyl derivatives of coenzyme A after hydrolysis of the thiol esters were converted to thioethers with [2,3-14C]N-ethylmaleimide and brought to radiochemical purity by chromatographic methods. While disulfides of coenzyme A were undetectable, 0.13 mumol CoASH and 1.17 mumol of total acyl-SCoA per g wet wt. were found. These data are consistent with the regulatory scheme of the energy metabolism of C. kluyveri previously proposed.

Catabolic and anabolic enzyme activities and energetics of acetone metabolism of the sulfate-reducing bacterium Desulfococcus biacutus

“…The intracellular acylCoA ester concentrations were in the same range as those measured for Clostridium kluyveri (36) and Clostridium acetobutylicum (4,17), and the esters were those postulated (Fig. 3) to be involved in the oxidation of acetone and the formation of poly-␤-hydroxybutyrate.…”