Glycoside hydrolase family 15
In molecular biology, glycoside hydrolase family 15 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. y9
Glycoside hydrolase family 15 comprises enzymes with several known activities; glucoamylase ; alpha-glucosidase ; glucodextranase.
Glucoamylase catalyses the release of D-glucose from the non-reducing ends of starch and other oligo- or poly-saccharides. Studies of fungal GA have indicated 3 closely clustered acidic residues that play a role in the catalytic mechanism. This region is also conserved in a recently sequenced bacterial GA.
The 3D structure of the pseudo-tetrasaccharide acarbose complexed with glucoamylase II from Aspergillus awamori var. X100 has been determined to 2.4A resolution. The protein belongs to the mainly alpha class, and contains 19 helices and 9 strands.
