All living organisms require nutrients to grow and reproduce. When nutrient quantity or quality is low, organisms reduce their growth rate and enter a dormant state. We now report that preserving proteins during dormancy speeds the return to a growth state. We establish that the bacterium Salmonella enterica reduces proteolysis when starved for a variety of nutrients. Salmonella reduces protein degradation by adenosine triphosphate (ATP)-dependent proteases by decreasing ATP amounts when starved for magnesium, carbon and nitrogen.　 The yeast Saccharomyces cerevisiae also reduces ATP amounts and ATP-dependent proteolysis when starved for nutrients. It raises a question why bacteria preserve protein pool from proteolysis during nutritional starvation.　 Drugs that increase ATP amounts promote ATP-dependent proteolysis and delay entry into the growth state from dormancy. Also, we are investigating critical proteins for regrowth of bacteria and chronic infection using proteomic, metabolomic and EMR analysis. Thus, the better the ability to preserve proteins during dormancy, the faster microbes exit the dormant state as soon as nutrients become available.