Updated project metadata. To uncover potential regulatory roles for acetylation, we analyzed how acetylation patterns and abundances change between logarithmic and stationary phase growth in Bacillus subtilis. Using acetyllysine peptide enrichment followed by label-free mass spectrometry-based proteomics, we identified over 2,300 unique acetylation sites on proteins that function in many essential pathways. By comparing the changes in acetylation with total cell protein abundances, we discover a subset of specific acetylation events that are stoichiometrically regulated under different growth conditions.