Pathways involved in pyruvate metabolism. Pyruvate (Pyr) can either be converted directly into phosphoenolpyruvate (blue arrows) or by utilising other pathways via the glyoxylate shunt and adjacent reactions (green arrows). Genes encoding enzymes that are on average more than twofold up- or downregulated in pyruvate grown cultures in comparison to acetate grown cultures are indicated by blue arrows (up-regulation in pyruvate grown cultures) and red arrows (down-regulation in pyruvate grown cultures). Enzyme abbreviations: AceA, isocitrate lyase; AceB/GlcB, malate synthase; Acn, aconitase; Acs, acetyl-CoA-synthetase; AckA, acetate kinase; Fum, fumarase; GltA, citrate synthase; Mdh, malate dehydrogenase; Pck, phosphoenolpyruvate carboxykinase; Pdh, pyruvate dehydrogenase; Pox, pyruvate oxidase; PpsA, phospoenolpyruvate synthase; Pta, phosphate acetyltransferase; Sdh, succinate dehydrogenase. Metabolite abbreviations: Ac, acetate; AcP, acetyl-phosphate; AcCoA, acetyl-CoA, Cit, citrate; Glx, glyoxylate; Icit, isocitrate; Succ, succinate; Fum, fumarate; Mal, malate; OAA, oxaloacetate; PEP, phosphoenolpyruvate; Pyr, pyruvate.