Identification of a mitochondrial alcohol dehydrogenase in Schizosaccharomyces pombe: new insights into energy metabolism

Crichton, Paul G., Affourtit, Charles and Moore, Anthony L. (2007) Identification of a mitochondrial alcohol dehydrogenase in Schizosaccharomyces pombe: new insights into energy metabolism. Biochemical Journal, 401 (2). pp. 459-464. ISSN 0264-6021

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Abstract

In the present study we have shown that mitochondria isolated from Schizosaccharomyces pombe exhibit antimycin A-sensitive oxygen uptake activity that is exclusively dependent on ethanol and is inhibited by trifluoroethanol, a potent inhibitor of ADH (alcohol dehydrogenase). Ethanol-dependent respiratory activity has, to our knowledge, not been reported in S. pombe mitochondria to date, which is surprising as it has been concluded previously that only one ADH gene, encoding a cytosolic enzyme, occurs in this yeast. Spectrophotometric enzyme assays reveal that ADH activity in isolated mitochondria is increased ∼16-fold by Triton X-100, which demonstrates that the enzyme is located in the matrix. Using genetic knockouts, we show conclusively that the novel mitochondrial ADH is encoded by adh4 and, as such, is unrelated to ADH isoenzymes found in mitochondria of other yeasts. By performing a modular-kinetic analysis of mitochondrial electron transfer, we furthermore show how ethanol-dependent respiratory activity (which involves oxidation of matrix-located NADH) compares with that observed when succinate or externally added NADH are used as substrates. This analysis reveals distinct kinetic differences between substrates which fully explain the lack of respiratory control generally observed during ethanol oxidation in yeast mitochondria.

Item Type: Article
Uncontrolled Keywords: alcohol dehydrogenase,mitochondrion,modular kinetics,nadh dehydrogenase,respiration,schizosaccharomyces pombe,ubiquinone pool
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
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Depositing User: Pure Connector
Date Deposited: 03 Nov 2016 11:00
Last Modified: 22 Apr 2020 01:54
URI: https://ueaeprints.uea.ac.uk/id/eprint/61220
DOI: 10.1042/BJ20061181

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