The inhibition of erythrocyte glyceraldehyde-3-phosphate dehydrogenase. In situ PMR studies.
The kinetics of inhibition of human erythrocyte glyceraldehyde-3-phosphate dehydrogenase by iodoacetate were studied in the intact cell and in vitro. The kinetics were determined using 1H-NMR to follow solvent exchange of 1H and 2H at the C-2 position of lactate. The exchange occurs via a series of enzyme-catalysed reactions, including that catalysed by glyceraldehyde-3-phosphate dehydrogenase. A direct assay with quenching of the inhibition was also used to check the results. Iodoacetate was shown to act as an active site-directed inhibitor of the dehydrogenase. The enzyme inhibition patterns, which are characterised by a binding step and a kinetic step, are similar in situ and in vitro. Membrane binding, however, was found to alter the inhibition pattern for the enzyme in vitro.
D003903:Deuterium; D004912:Erythrocytes / Q000201:enzymology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D007461:Iodoacetates / Q000494:pharmacology*; D019807:Iodoacetic Acid; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011485:Protein Binding; D011865:Radioisotope Dilution Technique
D007461:Iodoacetates; D003903:Deuterium; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D019807:Iodoacetic Acid