Acetate:Succinate CoA-transferase in the Hydrogenosomes of Trichomonas vaginalis

Acetate:succinate CoA-transferases (ASCT) are acetate-pro-ducing enzymes in hydrogenosomes, anaerobically functioning mitochondria and in the aerobically functioning mitochondria of trypanosomatids. Although acetate is produced in the hydrogeno-somes of a number of anaerobic microbial eukaryotes such as Trichomonas vaginalis, no acetate producing enzyme has ever been identified in these organelles. Acetate production is the last unidentified enzymatic reaction of hydrogenosomal carbohydrate metabolism.We identified a gene encoding an enzyme for acetate production in the genome of the hydrogenosome-containing pro-tozoan parasite T. vaginalis. This gene shows high similarity to Saccharomyces cerevisiae acetyl-CoA hydrolase and Clostridi-um kluyveri succinyl-CoA:CoA-transferase. Here we demonstrate that thisprotein is expressedand ispresent in thehydrogenosomes where it functions as theT. vaginalis acetate:succinate CoA-trans