In enzymology, a xyloglucan-specific endo-beta-1,4-glucanase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are xyloglucan and H<sub>2</sub>O, whereas its product is xyloglucan oligosaccharides.
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 [(1->6)-alpha-D-xylo]-(1->4)-beta-D-glucan glucanohydrolase. Other names in common use include XEG, xyloglucan endo-beta-1,4-glucanase, xyloglucanase, xyloglucanendohydrolase, XH, and 1,4-beta-D-glucan glucanohydrolase.
Family 12 was first identified in plant pathogens by discovery in Phytophthora spp.
As of late 2007, 15 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , , and .