β-Glucanase 1(thermostable) is a glucosidase located at the brush border of the small intestine, targeting β1→4 glycosidic bonds between glucose or glucose-substituted molecules (such as the disaccharide cellobiose). This enzyme is an exocellulase specific to various β-D-glycosidic substrates. It catalyzes the hydrolysis of non-reducing terminal residues of β-D-glucosides, releasing glucose.