Glycoside hydrolase family 19
In molecular biology, Glycoside hydrolase family 19 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 19 comprises enzymes with only one known activity; chitinase.
Chitinases are enzymes that catalyze the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine linkages in chitin polymers. Chitinases belong to glycoside hydrolase families 18 or 19. Chitinases of family 19 are enzymes from plants that function in the defence against fungal and insect pathogens by destroying their chitin-containing cell wall. Class IA/I and IB/II enzymes differ in the presence or absence of a N-terminal chitin-binding domain. The catalytic domain of these enzymes consist of about 220 to 230 amino acid residues.Active site
GH19 enzymes has a conserved sequence motif in its active site.
