What is "alpha,alpha-trehalase"

In enzymology, an alpha,alpha-trehalase is an enzyme with system name alpha,alpha-trehalose glucohydrolase. This enzyme catalyzes the chemical reaction

alpha,alpha-trehalose + HO $\rightleftharpoons$ 2 D-glucose

Thus, the two substrates of this enzyme are alpha,alpha-trehalose and HO, whereas its product is D-glucose.

This enzyme belongs to the family of hydrolases, specifically those glycosidases that hydrolyse O- and S-glycosyl compounds. The systematic name of this enzyme class is alpha,alpha-trehalose glucohydrolase. This enzyme is also called trehalase. This enzyme participates in starch and sucrose metabolism.