InterPro domain: IPR044791

Glycoside hydrolase family 16 GH16 comprises enzymes with a number of known activities; lichenase ( 3.2.1.73 ); xyloglucan xyloglucosyltransferase ( 2.4.1.207 ); agarase ( 3.2.1.81 ); kappa-carrageenase ( 3.2.1.83 ); endo-beta-1,3-glucanase ( 3.2.1.39 ); endo-beta-1,3-1,4-glucanase ( 3.2.1.6 ); endo-beta-galactosidase ( 3.2.1.103 ).

This entry includes a group of xyloglucan endotransglucosylase/hydrolases (XTHs) from plants [ 1 ]. Xyloglucan is a soluble hemicellulose with a backbone of beta-1,4-linked glucose units, partially substituted with alpha-1,6-linked xylopyranose branches. It binds noncovalently to cellulose, cross-linking the adjacent cellulose microfibrils, giving it a key structural role as a matrix polymer. XTHs catalyses xyloglucan endohydrolysis (XEH) and/or endotransglycosylation (XET) and are involved in the modification of cell wall structure by cleaving and, often, also re-joining xyloglucan molecules in primary plant cell walls [ 2 ].

This entry represents a subgroup of the glycoside hydrolase family 16. This entry includes beta-glucanases ( 3.2.1.73 ) from bacteria and xyloglucan endotransglucosylase/hydrolases (XTHs, 2.4.1.207 ) from plants.

1. The XTH gene family: an update on enzyme structure, function, and phylogeny in xyloglucan remodeling. Plant Physiol. 153, 456-66
2. Active gene expression of a xyloglucan endotransglucosylase/hydrolase gene, XTH9, in inflorescence apices is related to cell elongation in Arabidopsis thaliana. Plant Mol. Biol. 52, 473-82