Fig 3. Metabolomic analysis of methionine and cysteine metabolism in T. vaginalis and T. foetus.
T. vaginalis and T. foetus were grown for 20 h at 37°C in MDM which contains no added cysteine. Graphs show concentrations of metabolites (nmol/108 cells) calculated from peak intensity values using standard curves. There were no standards available for the mixed disulfide of cysteine and homocysteine (Cys:Hcy disulfide) and its concentration is represented by peak intensity/108 cells. Broken lines indicate the oxidation of sulfur amino acids to form disulfides. Enzymes found in the T. vaginalis genome are: 1, S-adenosylmethionine synthase; 2, S-adenosylmethionine dependent methyltransferase; 3, S-adenosylhomocysteine hydrolase; 4, methionine γ-lyase (MGL); 5, cysteine synthase (CS); 6, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase. CS from T. vaginalis is a multi-functional enzyme with broad specificity, as demonstrated in later sections. * More than 3-fold difference between species. P ≤ 0.001 (Paired T-Test, assuming equal variance).