Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.28 (lactic acid dehydrogenase)
 476 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transport of beta-galactosides by isolated membrane preparations from Escherichia coli strains containing a functional y gene is markedly stimulated by the conversion of D-lactate to pyruvate. The addition of D-lactate to these membrane preparations produces a 19-fold increase in the initial rate of uptake and a 10-fold stimulation of the steady-state level of intramembranal lactose or thiomethylgalactoside. Succinate, DL-alpha-hydroxybutyrate, and L-lactate partially replace D-lactate, but are much less effective; ATP and P-enolpyruvate, in addition to a number of other metabolites and cofactors, do not stimulate lactose transport by the vesicles. Lactose uptake by the membrane preparations in the presence of D-lactate requires oxygen, and is blocked by electron transport inhibitors and proton conductors; however, uptake is not significantly inhibited by high concentrations of arsenate or oligomycin. Furthermore, the P-enolpyruvate-P-transferase system is not involved in beta-galactoside transport by the E. coli membrane vesicles. The findings indicate that the beta-galactoside uptake system is coupled to the membrane-bound D-lactic dehydrogenase via an electron transport chain but does not involve oxidative phosphorylation.
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PMID:Beta-galactoside transport in bacterial membrane preparations: energy coupling via membrane-bounded D-lactic dehydrogenase. 439 55