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Nitrogen catabolite repression in Saccharomyces cerevisiae during wine fermentations
Gemma Beltran1, Maite Novo, Nicolas Rozès
1Unitat d'Enologia del Centre de Referència de Tecnologia d'Aliments, Dept. Bioquímica i Biotecnologia, Facultat d'Enologia de Tarragona, Universitat Rovira i Virgili, Ramón y Cajal, 70, 43005 Tarragona, Spain.
Abstract:
We carried out fermentations with several nitrogen sources in different concentrations and studied nitrogen regulation by following the transcriptional profile of the general amino-acid permease (GAP1) and the ammonium permeases (MEP1, MEP2, MEP3). In wine fermentations the cells evolve from a nitrogen-repressed situation at the beginning of the process to a nitrogen-derepressed situation as the nitrogen is consumed. These nitrogen-repressed/derepressed conditions determined the different patterns of ammonium and amino-acid consumption. Arginine and alanine were hardly used under the repressed conditions, while the uptake of branched-chain and aromatic amino acids increased.