A. Gold, E. Legrand, G. Sánchez
Sep 25, 1971
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Influential Citations
35
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Journal
The Journal of biological chemistry
Abstract
Abstract 5-Gluconolactone is a potent inhibitor of rabbit muscle phosphorylase a in the presence of saturating AMP. Kinetic analysis leads to the conclusion that the inhibitor binds most strongly to the enzyme-glycogen-Pi complex (Kapi = 0.025 mm), but weaker binding is also observed with the enzyme-glycogen-α-d-glucopyranose 1-phosphate complex, the enzyme-glycogen complex, the enzyme-Pi complex, and the free enzyme. Dissociation constants for each of the observed inhibitor complexes have been evaluated. The kinetic data is consistent with a model in which 5-gluconolactone binds to the site in the enzyme that normally binds the glucosyl residue that is transferred between polysaccharide and Pi in the catalytic reaction. 5-Gluconolactone may be an analogue of the substrate part of the transition state of the phosphorylase reaction.