Chemical modification of aldehyde dehydrogenase by a vinyl ketone analogue of an insect pheromone

摘要: A major component of the sex pheromone from tobacco budworm moth Heliothis virescens is a C16 straight-chain aldehyde with single unsaturation at eleventh position. The pheromones are inactivated when metabolized to their corresponding acids by insect dehydrogenase. During this investigation it was demonstrated that good substrate for human dehydrogenase (EC 1.2.1.3) isoenzymes E1 and E2 Km Kcat. values pH 7.0 2 microM 0.4 mumol NADH/min per mg 0.6 0.24 respectively. vinyl ketone analogue inhibited metabolism; also Total inactivation both achieved stoichiometric (equal or less than subunit number) concentrations ketone, incorporating 2.1-2.6 molecules/molecule enzyme. Substrate protection observed in presence parent 5′-AMP. Peptide maps tryptic digests isoenzyme modified 3H-labelled showed incorporation occurred into peptide peak. labelled further purified on h.p.l.c. sequenced. label incorporated cysteine-302 primary structure isoenzyme, thus indicating located area active site Affinity labelling ketones may prove be general utility biochemical studies these enzymes.