title: alpha-Ethynyl and alpha-vinyl analogues of ornithine as enzyme-activated inhibitors of mammalian ornithine decarboxylase.
abstract: alpha-Ethynyl- and alpha-vinylornithine were designed and synthesized as potential enzyme-activated inhibitors of mammalian ornithine decarboxylase. These two new inhibitors produce both immediate and time-dependent inhibition of rat liver ornithine decarboxylase in vitro. The inhibitions exhibition saturation kinetics. The apparent dissociation constants (KI) are 10 and 810 microM, and the times of half-inactivation at infinite concentration of inhibitor (t1/2) are 8.5 and 27 min, respectively, for alpha-ethynyl- and alpha-vinylornithine. In rats, alpha-ethynylornithine causes a rapid dose-dependent decrease of ornithine decarboxylase activity in prostate and, to a lesser extent, in thymus and testis.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors*; D055598:Chemical Phenomena; D002621:Chemistry; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D009952:Ornithine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D065108:Ornithine Decarboxylase Inhibitors; D051381:Rats
chemical_list: D065108:Ornithine Decarboxylase Inhibitors; D009952:Ornithine; D002262:Carboxy-Lyases