Trehalose is thought to be one of the reserve carbohydrates in the
yeast Saccharomyces cerevisiae and can constitute up to 25% of the
dry mass of a cell, depending on the environmental conditions (1). It
is synthesized from UDP-glucose and glucose-6-phosphate in a
two-step reaction involving trehalose-6-phosphate synthase encoded
by TPS1 (2, 3) and trehalose-6-phosphate phosphatase encoded by
TPS2 (4). The activities of these 2 enzymes are brought about by a
multi-protein complex, which contains a third component encoded by
TSL1 with no obvious enzymatic activity (3). Trehalose is hydrolyzed
into glucose by neutral trehalases encoded by NTH1 and NTH2 (5, 6)
or by an acid-vacuolar trehalase encoded by ATH1