Studies on succinate dehydrogenase. VI. Inhibition by monocarboxylic acids
1970; Elsevier BV; Volume: 198; Issue: 3 Linguagem: Inglês
10.1016/0005-2744(70)90120-8
ISSN1878-1454
AutoresW.P. Zeylemaker, A.D.M. Klaasse, E.C. Slater, C. Veeger,
Tópico(s)Hemoglobin structure and function
Resumo1. Bicarbonate is a competitive inhibitor of succinate dehydrogenase (succinate: (acceptor) oxidoreductase, EC 1.3.99.1). 2. Bicarbonate is bound to the enzyme at two sites, with virtually equal affinities. 3. A method for the determination of the inhibitor constant for this type of inhibition is proposed. The Ki (intrinsic dissociation constant at each binding site) was found to be 12 mM. 4. Formate (Ki = 120 mM), glucolate (Ki = 120 mM) and gloxylate (Ki = 21 mM) are all competitive inhibitors binding at two sites. Acetate and propionate do not inhibit. 5. It is suggested that an interaction between the enzyme and a hydroxyl group in the a-position leads to a binding energy of 0.9–1.4 kcal/mole, in addition to the binding between carboxylate groups and basic groupings in the enzyme.
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