Enzymes of the central metabolism with the biosynthetic pathway of l-valine in C. glutamicum and the synthetic pathway from ketoisovalerate to isobutanol. Abbreviations: Adh, alcohol dehydrogenase; AHAIR, acetohydroxyacid isomeroreductase; AHAS, acetohydroxyacid synthase; AK, acetate kinase; DHAD, dihydroxyacid dehydratase; FUM, fumarase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; KIVD, 2-ketoacid decarboxylase from L. lactis; LdhA, l-lactate dehydrogenase; MalE, malic enzyme; Mdh, malate dehydrogenase; MQO, malate:quinone oxidoreductase; PCx, pyruvate carboxylase; PDHC, pyruvate dehydrogenase complex; PEP, phosphoenolpyruvate; PEPCk, PEP carboxykinase; PEPCx, PEP carboxylase; PK, pyruvate kinase; PntAB, membrane bound transhydrogenase from E. coli; PTA, phosphotransacetylase; PQO, pyruvate:quinone oxidoreductase; SDH, succinate dehydrogenase; TA, transaminase B; TCA, tricarboxylic acid.