Regulation of the redox potential of general acyl-CoA dehydrogenase by substrate binding.
Significant thermodynamic changes have been observed for general acyl-CoA dehydrogenase (GAD) upon substrate binding. Spectroelectrochemical studies of GAD and several of its substrates have revealed that these substrates are essentially isopotential for chain lengths of C-4 to C-16 (E 0' =-0.038 to -0.045 V vs SHE). When GAD is bound by these substrates, a dramatic shift in the midpoint potential of the enzyme is observed (E 0' = -0.136 V for ligand-free GAD and -0.026 V for acyl-CoA-bound GAD), thus allowing a thermodynamically favorable transfer of electrons from substrate to enzyme. This contrasts with values reported elsewhere. From these data an isopotential scheme of electron delivery into the electron-transport chain is proposed.
Lenn
N D
ND
Department of Chemistry, University of Minnesota, Minneapolis 55455.
Stankovich
M T
MT
Liu
H W
HW
D044944:Acyl-CoA Dehydrogenases / Q000378:metabolism*; D000818:Animals; D010084:Oxidation-Reduction; D013379:Substrate Specificity; D013552:Swine; D013816:Thermodynamics
D044944:Acyl-CoA Dehydrogenases