Differential redox potential between the human cytosolic and mitochondrial branched-chain aminotransferase

Coles, Steven J.; Hancock, John T.; Conway, Myra E.

Abstract

The human branched-chain aminotransferase (hBCAT) isoenzymes are CXXC motif redox sensitive homodimers central to glutamate metabolism in the central nervous system. These proteins respond differently to oxidation by H 2O 2, NO, and S-glutathionylation, suggesting that the redox potential is distinct between isoenzymes. Using various reduced to oxidized glutathione ratios (GSH:GSSG) to alter the redox environment, we demonstrate that hBCATc (cytosolic) has an overall redox potential that is 30 mV lower than hBCATm (mitochondrial). Furthermore, the CXXC motif of hBCATc was estimated to be 80 mV lower, suggesting that hBCATm is more oxidizing in nature. Western blot analysis revealed close correlations between hBCAT S-glutathionylation and the redox status of the assay environment, offering the hBCAT isoenzymes as novel biomarkers for cytosolic and mitochondrial oxidative stress. © The Author 2011.

Citation

Coles, S. J., Hancock, J. T., & Conway, M. E. (2012). Differential redox potential between the human cytosolic and mitochondrial branched-chain aminotransferase. Acta Biochimica et Biophysica Sinica, 44(2), 172-176. https://doi.org/10.1093/abbs/gmr103

• Journal Article Type: Article
• Publication Date: Feb 1, 2012
• Journal: Acta Biochimica et Biophysica Sinica
• Print ISSN: 1672-9145
• Electronic ISSN: 1745-7270
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• Volume: 44
• Issue: 2
• Pages: 172-176
• DOI: https://doi.org/10.1093/abbs/gmr103
• Keywords: glutathione, Nernst equation, redox potential, branched-chain aminotransferase
• Public URL: https://uwe-repository.worktribe.com/output/952306
• Publisher URL: http://dx.doi.org/10.1093/abbs/gmr103