FIG. 3.
Tentative scheme for the citric acid cycle of H. pylori based on genome sequence data and biochemical data. Unusual enzymes are labeled with an asterisk. Pyr, pyruvate; AcCoA, acetyl-CoA; Cit, citrate; Icit, isocitrate; Kg, 2-ketoglutarate; Suc-CoA, succinyl-CoA; Suc, succinate; Fum, fumarate; Mal, malate; Oaa, oxaloacetate; Fdox and Fdred: oxidized and reduced ferredoxin, respectively; MQ and MQH2, oxidized and reduced menaquinone, respectively. Enzymes: 1, pyruvate:ferredoxin oxidoreductase; 2, citrate synthase; 3, aconitase; 4, isocitrate dehydrogenase; 5, α-ketoglutarate:ferredoxin oxidoreductase; 6, succinyl-CoA acetoacetyl-CoA transferase; 7, fumarate reductase (SDH); 8, fumarase; 9, malate:quinone oxidoreductase. EC numbers and corresponding H. pylori genes of all enzymes except the MQO can be found elsewhere (19).