Carbohydrate-binding, chitobiase/hexosaminidase-type, N-terminal <p>This domain represents the N-terminal domain in chitobiases and beta-hexosaminidases <db_xref db="EC" dbkey="3.2.1.52"/>. Chitobiases degrade chitin, which forms the exoskeleton in insects and crustaceans, and which is one of the most abundant polysaccharides on earth [<cite idref="PUB00007713"/>]. Beta-hexosaminidases are composed of either a HexA/HexB heterodimer or a HexB homodimer, and can hydrolyse diverse substrates, including GM(2)-gangliosides; mutations in this enzyme are associated with Tay-Sachs disease [<cite idref="PUB00016244"/>]. HexB is structurally similar to chitobiase, consisting of a beta sandwich structure; this structure is similar to that found in the cellulose-binding domain of cellulase from <taxon tax_id="1708">Cellulomonas fimi</taxon> (<db_xref db="INTERPRO" dbkey="IPR001919"/>), suggesting that it may function as a carbohydrate-binding domain.</p>