<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> Members of this family belong to the chitinase class II group which includes chitinase, chitodextrinase and the killer toxin of <taxon tax_id="28985">Kluyveromyces lactis</taxon> (Yeast) (Candida sphaerica) and all belong to glycoside hydrolase, family 18 <db_xref db="CAZY" dbkey="GH18"/>. The chitinases hydrolyse chitin oligosaccharides.</p>