In vitro fenoprofenyl-coenzyme A thioester formation: interspecies variations
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Published on: March 28, 2017
1Department of Metabolic Toxicology, School of Veterinary Medicine of Lyon, Marcy-l'Etoile, France.
Abstract:
In vitro coenzyme A thioester formation from (-)-(R)-fenoprofen (FPF) and palmitic acid has been studied using liver microsomes from rat, guinea pig, sheep, and dog. In every species with both palmitic acid or (-)-(R)-fenoprofen, the Lineweaver-Burk plot was linear in the substrate concentration range used and as a consequence agrees with the involvement of only one isoenzyme (or different isoenzymes of similar Km values). The Vmax values for the thioesterification of (-)-(R)-fenoprofen present large species variations from 2.1 +/- 1.0 with sheep liver microsomes to 60.6 +/- 11 nmol/min/mg with dog liver microsomes. These values statistically significantly correlate (r = 0.94) to the Vmax values observed when palmitic acid was used as a substrate. Furthermore palmitic acid inhibited (-)-(R)-fenoprofen-CoA formation in the same extent in all animal species. The stereoselectivity of the thioesterification was also species dependent.
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