Hydrolyzes intracellular trehalose to glucose (PubMed:22320399, PubMed:29087344) (Probable). The disaccharide trehalose serves as a storage carbohydrate that is mobilized during nutrient stress (Probable). Regulates the level of trehalose as a protectant for cell integrity during heat stress (PubMed:7883049, PubMed:7730323). alpha,alpha-trehalose + H2O = alpha-D-glucose + beta-D-glucose Activated by calcium (PubMed:22320399). Activated by protein kinase A (PKA)-mediated phosphorylation (PubMed:22320399). kcat is 71 sec(-1) for trehalose (in the presence of BMH1, at pH 7.5 and 30 degrees Celsius). kcat is 6.2 sec(-1) for trehalose (in the presence of 5 mM calcium, at pH 7.5 and 30 degrees Celsius). kcat is 42 sec(-1) for trehalose (in the presence of 5 mM calcium and BMH1, at pH 7.5 and 30 degrees Celsius). Carbohydrate degradation. Monomer (PubMed:22320399, PubMed:29087344). Interacts with BMH1 dimers; the interaction is direct and activates NTH1 (PubMed:29087344, PubMed:22320399). Interacts with BMH2 (PubMed:22320399). Induced during thermal stress (at protein level) (PubMed:7883049, PubMed:9276477). Induced by oxidative stress (hydrogen peroxide, sodium arsenite) (at protein level) (PubMed:9276477). Induced by copper stress (at protein level) (PubMed:9276477). Induced by protein synthesis inhibitor (cycloheximide) (PubMed:9276477). Phosphorylated by protein kinase A (PKA); phosphorylation at Ser-60 and Ser-83 is required for activation by the 14-3-3 proteins BMH1 and BMH2. Increases cellular trehalase level during thermal stress (PubMed:7730323). Increases sensitivity to heat shock (PubMed:7730323, PubMed:7883049). Decreases growth on the non-fermentable carbon source glycerol; simultaneous knockout of ATH1 exacerbates the effect (PubMed:7883049). Present with 1840 molecules/cell in log phase SD medium. Belongs to the glycosyl hydrolase 37 family.