Kinetic mechanism of glutaryl-CoA dehydrogenase.
Glutaryl-CoA dehydrogenase (GCD) is a homotetrameric enzyme containing one noncovalently bound FAD per monomer that oxidatively decarboxylates glutaryl-CoA to crotonyl-CoA and CO2. GCD belongs to the family of acyl-CoA dehydrogenases that are evolutionarily conserved in their sequence, structure, and function. However, there are differences in the kinetic mechanisms among the different acyl-CoA dehydrogenases. One of the unanswered aspects is that of the rate-determining step in the steady-state turnover of GCD. In the present investigation, the major rate-determining step is identified to be the release of crotonyl-CoA product because the chemical steps and reoxidation of reduced FAD are much faster than the turnover of the wild-type GCD. Other steps are only partially rate-determining. This conclusion is based on the transit times of the individual reactions occurring in the active site of GCD.
Rao
K Sudhindra
KS
Department of Pediatrics, University of Colorado at Denver and Health Sciences Center, 12800 East Nineteenth Avenue, P18-4404B, Mail Stop 8313, P.O. Box 6511, Aurora, Colorado 80045-0511, USA.
Albro
Mark
M
Dwyer
Timothy M
TM
Frerman
Frank E
FE
D000214:Acyl Coenzyme A / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D003653:Decarboxylation; D041961:Deuterium Exchange Measurement; D004579:Electron Transport; D004735:Energy Transfer; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D050770:Glutaryl-CoA Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D010084:Oxidation-Reduction; D011522:Protons; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D011522:Protons; D005182:Flavin-Adenine Dinucleotide; C032423:glutaconyl-coenzyme A; C010701:crotonyl-coenzyme A; D050770:Glutaryl-CoA Dehydrogenase