Antonie van Leeuwenhoek

, Volume 102, Issue 1, pp 163–175

Mitochondrial involvement to methylglyoxal detoxification: d-Lactate/Malate antiporter in Saccharomyces cerevisiae

Original Paper

DOI: 10.1007/s10482-012-9724-0

Cite this article as:
Pallotta, M.L. Antonie van Leeuwenhoek (2012) 102: 163. doi:10.1007/s10482-012-9724-0

Abstract

Research during the last years has accumulated a large body of data that suggest that a permanent high flux through the glycolytic pathway may be a source of intracellular toxicity via continuous generation of endogenous reactive dicarbonyl compound methylglyoxal (MG). MG detoxification by the action of the glyoxalase system produces d-lactate. Thus, this article extends our previous work and presents new insights concerning d-lactate fate in aerobically grown yeast cells. Biochemical studies using intact functional mitochondrial preparations derived from Saccharomyces cerevisiae show that d-lactate produced in the extramitochondrial phase can be taken up by mitochondria, metabolised inside the organelles with efflux of newly synthesized malate. Experiments were carried out photometrically and the rate of malate efflux was measured by use of NADP+ and malic enzyme and it depended on the rate of transport across the mitochondrial membrane. It showed saturation characteristics (Km = 20 μM; Vmax = 6 nmol min−1 mg−1 of mitochondrial protein) and was inhibited by α-cyanocinnamate, a non-penetrant compound. Our data reveal that reducing equivalents export from mitochondria is due to the occurrence of a putative d-lactate/malate antiporter which differs from both d-lactate/pyruvate antiporter and d-lactate/H+ symporter as shown by the different Vmax values, pH profile and inhibitor sensitivity. Based on these results we propose that d-lactate translocators and d-lactate dehydrogenases work together for decreasing the production of MG from the cytosol, thus mitochondria could play a pro-survival role in the metabolic stress response as well as for d-lactate-dependent gluconeogenesis.

Keywords

Saccharomyces cerevisiae mitochondriad-Lactate metabolismMalate transportMethylglyoxalReactive dicarbonyl compoundGluconeogenesis

Abbreviations

SCM

Saccharomyces cerevisiae mitochondria

α-CCN

α-Cyanocinnamate

MG

Methylglyoxal

FCCP

Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone

ΔΨ

Membrane potential

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Department of Health SciencesUniversity of MoliseCampobassoItaly