M. Yoshikawa, J. Eckert, N. Keen
Oct 1, 1976
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Influential Citations
11
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Journal
Pesticide Biochemistry and Physiology
Abstract
sec-Butylamine at 5 mM inhibited the oxidation of pyruvate by mitochondria isolated from hyphae of Penicillium digitalum, but had little effect on the oxidation of citrate, isocitrate, succinate, malate, acetyl-coenzyme A, or reduced nicotinamide adenine dinucleotide. sec-Butylamine did not interfere with oxidative phosphorylation, as evidenced by similar PO ratios in treated and control mitochondria. The pyruvate dehydrogenase complex (EC 1.2.4.1) isolated from young hyphae of P. digitatum was inhibited strongly by 20 mM sec-butylamine, whereas other tricarboxylic acid cycle enzymes were only slightly affected at most. Inhibition of the pyruvate dehydrogenase complex by sec-butylamine was competitive with respect to pyruvate. The Ki for sec-butylamine in the reaction was 1.38 × 10−2 M, and the Km for pyruvate was 2.28 × 10−4 M. These observations and other evidence derived from studies with intact hyphae support the hypothesis that the pyruvate dehydrogenase complex is the primary site of the fungistatic action of sec-butylamine.