title: Inhibition of glyceraldehyde-3-phosphate dehydrogenase by phosphorylated epoxides and alpha-enones.
abstract: Pentalenolactone and koningic acid are antibiotics known for their potent inhibition of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase. The reactive groups present in these antibiotics are, respectively, an epoxide and an alpha-enone, which form covalent bonds with an active-site cysteine residue of the enzyme. This information was used for the design of two series of glyceraldehyde 3-phosphate analogues with similar reactive groups that could function as potential irreversible inhibitors of glyceraldehyde-3-phosphate dehydrogenase. Inactivation kinetics, NMR analysis, protection experiments, and titration of free cysteine residues together indicate that the inhibitors bind to the active site of the enzyme and form a covalent bond with the active-site cysteine residue of the enzyme. Binding probably takes place at the inorganic phosphate site of the enzyme and may lead to a conformational change. Comparison of the reactivities of the inhibitors for the glycosomal enzyme from the protozoan parasite Trypanosoma brucei and the rabbit muscle enzyme revealed that some of them had a preference for the trypanosome enzyme. When their effect was measured on the multiplication of trypanosome in vitro cultures, one inhibitor appeared to exhibit an inhibitory effect at a concentration significantly lower than the trypanocidal drugs, pentamidin and (difluoromethyl)ornithine, that are routinely used in the treatment of African sleeping sickness.
authors.affiliation: Laboratoire de Chimie Organique Biologique, URA CNRS 470, Université Paul Sabatier, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Willson
authors.forename: N
authors.initials: N
authors.lastname: Lauth
authors.forename: J
authors.initials: J
authors.lastname: Perie
authors.forename: M
authors.initials: M
authors.lastname: Callens
authors.forename: F R
authors.initials: FR
authors.lastname: Opperdoes
mesh_terms: D000818:Animals; D001665:Binding Sites; D003545:Cysteine; D004852:Epoxy Compounds / Q000494:pharmacology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors*; D007659:Ketones / Q000494:pharmacology*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D008958:Models, Molecular; D008962:Models, Theoretical; D015394:Molecular Structure; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D013329:Structure-Activity Relationship; D014346:Trypanosoma brucei brucei / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*
chemical_list: D004852:Epoxy Compounds; D007659:Ketones; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D003545:Cysteine