In molecular biology, glycoside hydrolase family 39 is a family of glycoside hydrolases.
Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 39 CAZY GH_39 comprises enzymes with several known activities; alpha-L-iduronidase (); beta-xylosidase ().
The most highly conserved regions in these enzymes are located in their N-terminal sections. These contain a glutamic acid residue which, on the basis of similarities with other families of glycosyl hydrolases, probably acts as the proton donor in their catalytic mechanism.