Differential changes in the activity of cytosolic and vacuolar trehalases along the growth cycle of Saccharomyces cerevisiae

摘要: Saccharomyces cerevisiae cells contain two intracellular and soluble trehalases with distinct subcellular location (cytosol vacuoles, respectively). Both enzymes showed an opposite pattern of activity along the growth cycle. Activity cytosolic trehalase was high in growing exponentially on fermentable sugars (glucose, mannose or galactose) sharply decayed as cultures enter stationary phase coinciding beginning trehalose biosynthesis. By contrast, vacuolar only detectable glucose-grown resting respiratory substrates (glycerol ethanol). This enzyme partially derepressed mutant hex2, which is deficient glucose repression. Addition fresh YPD medium to stationary-phase induced sudden reactivation concomitant slower inactivation trehalase. However, addition various nitrogen sources alone had a minor effect both activities. The presence cycloheximide no trehalase, whereas completely blocked appearance suggesting requirement protein synthesis 'de novo'.