PYRUVATE METABOLISM IN HELICOBACTER-PYLORI

The metabolism of pyruvate by Helicobacter pylori was investigated emp loying one- and two-dimensional H-1 and C-13 nuclear magnetic resonanc e spectroscopy. Generation of pyruvate from L-serine in incubations wi th whole cell lysates indicated the presence of serine dehydratase act ivity in the bacterium. Pyruvate was formed also in cell suspensions a nd lysates from phosphoenol pyruvate. Metabolically competent cells in cubated aerobically with pyruvate yielded alanine, lactate, acetate, f ormate, and succinate. The production of alanine and lactate indicated the presence of alanine transaminase and lactate dehydrogenase activi ties, respectively. Accumulation of acetate and formate as metabolic p roducts provided evidence for the existence of a mixed-acid fermentati on pathway in the microorganism. Formation of succinate suggested the incorporation of the pyruvate carbon skeleton into the Kreb's cycle. A ddition of pyruvate to various liquid culture media did not affect bac terial growth or loss of viability. The variety of products formed usi ng pyruvate as the sole substrate showed the important role of this me tabolite in the energy metabolism of H. pylori.