Glycoside hydrolase, family 8, conserved site <p>O-Glycosyl hydrolases <db_xref db="EC" dbkey="3.2.1."/> 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 glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [<cite idref="PUB00004870"/>, <cite idref="PUB00005266"/>]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.</p><p>Glycoside hydrolase family 8 <db_xref db="CAZY" dbkey="GH8"/> comprises enzymes with several known activities; endoglucanase (<db_xref db="EC" dbkey="3.2.1.4"/>); lichenase (<db_xref db="EC" dbkey="3.2.1.73"/>); chitosanase (<db_xref db="EC" dbkey="3.2.1.132"/>). These enzymes were formerly known as cellulase family D [<cite idref="PUB00001778"/>]. </p><p>The most conserved region in these enzymes is a stretch of about 20 residues that contains two conserved aspartates. The first asparatate is thought [<cite idref="PUB00005276"/>] to act as the nucleophile in the catalytic mechanism. This region as a signature pattern in this entry.</p>