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Abstract
The kinetic properties of citrate synthase from Candida 107 were examined. Adenine nucleotides were inhibitory to enzyme activity, the order of efficacy being ATP > ADP > AMP. Inhibition by ATP was competitive with respect to acetyl-CoA and mixed with respect to oxaloacetate. Combinations of adenine nucleotides giving simulated energy charge values were also inhibitory, though the total adenine nucleotide concentration was of greater significance than the relative proportions of each in determining the degree of inhibition. When Mg2+was added at a concentration sufficient to saturate the adenine nucleotides, the inhibition was almost entirely relieved. The apparent absence of any rigorous control of citrate synthase by adenine nucleotides in oleaginous micro-organisms is consistent with previous observations that the flow of carbon through the glycolytic and pentose phosphate pathways to pyruvate and thence to citrate should be uninterrupted during the process of lipid accumulation.
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