title: Re-characterisation of Saccharomyces cerevisiae Ach1p: fungal CoA-transferases are involved in acetic acid detoxification.
abstract: Saccharomyces cerevisiae and Neurospora crassa mutants defective in the so-called acetyl-CoA hydrolases Ach1p and Acu-8, respectively, display a severe growth defect on acetate, which is most strongly pronounced under acidic conditions. Acetyl-CoA hydrolysis is an energy wasting process and therefore denoted as a biochemical conundrum. Acetyl-CoA hydrolases show high sequence identity to the CoA-transferase CoaT from Aspergillus nidulans. Therefore, we extensively re-characterised the yeast enzyme. Ach1p showed highest specific activity for the CoASH transfer from succinyl-CoA to acetate and only a minor acetyl-CoA-hydrolase activity. Complementation of an ach1 mutant with the coaT gene reversed the growth defect on acetate confirming the in vivo function of Ach1p as a CoA-transferase. Our results imply that Ach1p is involved in mitochondrial acetate detoxification by a CoASH transfer from succinyl-CoA to acetate. Thereby, Ach1p does not perform the energy wasting hydrolysis of acetyl-CoA but conserves energy by the detoxification of mitochondrial acetate.
authors.affiliation: Leibniz Institute for Natural Product Research and Infection Biology e.V., -Hans Knoell Institute-, Research Group Microbial Biochemistry and Physiology, Jena, Germany.
authors.forename: Christian B
authors.initials: CB
authors.lastname: Fleck
authors.forename: Matthias
authors.initials: M
authors.lastname: Brock
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000378:metabolism; D000104:Acetyl-CoA Hydrolase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008928:Mitochondria / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D000105:Acetyl Coenzyme A; D000104:Acetyl-CoA Hydrolase; D019342:Acetic Acid