| Summary: | Peroxiredoxins are a family of peroxide-degrading enzymes for challenging oxidative stress. They receive their reducing power from redox-controlling proteins called thioredoxins, and these, in turn, from thioredoxin reductase. The main cytosolic peroxiredoxin is Tsa1, a moonlighting protein that also acts as protein chaperone a redox switch controlling some metabolic events. Gene deletion of peroxiredoxins in wine yeasts indicate that <i>TSA1</i>, thioredoxins and thioredoxin reductase <i>TRR1</i> are required for normal growth in medium with glucose and sucrose as carbon sources. <i>TSA1</i> gene deletion also diminishes growth in molasses, both in flasks and bioreactors. The <i>TSA1</i> mutation brings about an expected change in redox parameters but, interestingly, it also triggers a variety of metabolic changes. It influences trehalose accumulation, lowering it in first molasses growth stages, but increasing it at the end of batch growth, when respiratory metabolism is set up. Glycogen accumulation at the entry of the stationary phase also increases in the <i>tsa1</i>Δ mutant. The mutation reduces fermentative capacity in grape juice, but the vinification profile does not significantly change. However, acetic acid and acetaldehyde production decrease when <i>TSA1</i> is absent. Hence, <i>TSA1</i> plays a role in the regulation of metabolic reactions leading to the production of such relevant enological molecules.
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