Inhibition of pig-heart citrate synthase by carboxylic acids structurally related to oxaloacetate.

摘要: 1 The kinetics of inhibition citrate synthase by a number dicarboxylic and tricarboxylic acids have been examined. Inhibition parameters providing information about equilibrium constants for ligand-binding to free enzyme the binary · oxaloacetate complex were determined under Michaelis-Menten conditions. Ligand-binding acetyl-CoA was studied new kinetic approach, based upon an examination effect inhibitors on second-degree rate behaviour enzyme. 2 Carboxylic may bind site (as anions), as well analogues). Depending relative strength these interactions, competitive with either or both substrates is observed. 3 Kinetically estimated binding different species in catalytic mechanism are reported. The results obtained show that carboxylic acids, general, non-cooperatively substrates. 4 The affinity increases 10-fold D-malate. mechanistic significance this previously reported heterotropic cooperativity effects system discussed. It suggested certain containing D-malate substructure induces conformational change enzyme. This serves purpose creating proper accomodation acyl moiety at center