Reversible effects of cross-linking on the regulatory cooperativity of Acinetobacter citrate synthase.
Citrate synthase was purified from Acinetobacter calcoaceticus and treated with the cleavable cross-linking reagent dithiobis(succinimidyl propionate). Cross-linking of the enzyme resulted in the abolition of the sigmoidal responses to inhibition by NADH and re-activation by AMP displayed by the native enzyme. Inhibition and re-activation were still observed but without any cooperativity. Cleavage of the disulphide bonds in the cross-links by treatment with dithiothreitol restored the sigmoidal characteristics of both inhibition and re-activation.
D000150:Acinetobacter / Q000201:enzymology*; D000249:Adenosine Monophosphate / Q000494:pharmacology; D002950:Citrate (si)-Synthase / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004789:Enzyme Activation; D007700:Kinetics; D009243:NAD / Q000494:pharmacology; D010084:Oxidation-Reduction; D007652:Oxo-Acid-Lyases / Q000378:metabolism*; D013388:Succinimides / Q000494:pharmacology*
D003432:Cross-Linking Reagents; D013388:Succinimides; D009243:NAD; D000249:Adenosine Monophosphate; D002950:Citrate (si)-Synthase; D007652:Oxo-Acid-Lyases; C011240:dithiobis(succinimidylpropionate)