Citrate Uptake in Exchange with Intermediates in the Citrate Metabolic Pathway in Lactococcus lactis IL1403

摘要: Carbohydrate/citrate cometabolism in Lactococcus lactis results the formation of flavor compound acetoin. Resting cells strain IL1403(pFL3) rapidly consumed citrate while producing acetoin when substoichiometric concentrations glucose or l-lactate were present. A proton motive force was generated by electrogenic exchange and lactate catalyzed transporter CitP consumption decarboxylation reactions pathway. In absence l-lactate, biphasic. During first phase, hardly any consumed. second converted rapidly, but without Instead, significant amounts intermediates pyruvate α-acetolactate, end product acetate, excreted from cells. It is shown that acetate are with uptake CitP. The availability exchangeable substrates cytoplasm determines both rate profile. follows metabolism L. splits up two routes after pyruvate, one well-characterized route yielding other a new acetate. flux distribution between branches changes 85:15 presence to 30:70 pyruvate. greatest zero suggesting pathway does not generate force.