Noncovalent modulation by ATP of the acyl transfer from acyl-glyceraldehyde-3-phosphate dehydrogenase to phosphate |
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Authors: | O P Malhotra S A Bernhard |
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Institution: | Institute of Molecular Biology, University of Oregon, Eugene 97403. |
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Abstract: | The effect of ATP on the formation, spectral properties, and reactions of beta-(2-furyl)acryloyl]glyceraldehyde-3-phosphate dehydrogenase (FA-GPDH) has been investigated. The chromophoric FA-GPDH has the advantage of providing spectrophotometric signals of the interaction of acyl enzyme with nucleotides and dinucleotides. The results are consistent with the exclusive existence of two acyl-enzyme conformations previously inferred from the interaction of the acyl enzyme with NAD+ and NADH. ATP interaction stabilizes a conformation different from that stabilized by NAD+. The inhibitory effects of ATP on these reactions are consistent with the reported inhibitory effect of ATP on the steady-state reaction with the true substrate. The physiological significance of these results to the regulation of glycolysis, via the ligand-dependent fate of 3-phosphoglycerol-GPDH, is discussed. |
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