This project aimed to characterize the proteomic profile of Levilactobacillus brevis CRL 2013, a γ-aminobutyric acid (GABA)-producing lactic acid bacterium, grown under different nitrogen sources (CDMg, CDMgC, CDMgYE). Proteins were extracted from cultures, digested with trypsin, and analyzed using nanoLC coupled to high-resolution tandem mass spectrometry on a Q-Exactive Orbitrap instrument. The study provides insights into protein expression changes linked to metabolic adaptation under varying nutritional conditions. Raw MS data and search engine results are deposited to enable re-analysis and comparison with related studies.