<p>It has been shown [<cite idref="PUB00000503"/>, <cite idref="PUB00002122"/>] that the following glycosyl hydrolases can be classified into a single family on the basis of sequence similarities: </p><ul><li>Inulinase (<db_xref db="EC" dbkey="3.2.1.7"/>) (or inulase) from the fungi <taxon tax_id="4911">Kluyveromyces marxianus</taxon> (Yeast) (Candida kefyr). </li> <li>Beta-fructofuranosidase (<db_xref db="EC" dbkey="3.2.1.26"/>), commonly known as invertase in fungi and plants and as sucrase in bacteria (gene sacA or scrB). </li><li>Raffinose invertase (<db_xref db="EC" dbkey="3.2.1.26"/>) (gene rafD) from <taxon tax_id="562">Escherichia coli</taxon> raffinose plasmid pRSD2. </li><li>Levanase (<db_xref db="EC" dbkey="3.2.1.65"/>) (gene sacC) from <taxon tax_id="1423">Bacillus subtilis</taxon>. </li></ul><p>One of the conserved regions in these enzymes is located in the N-terminal section and contains an aspartic acid residue which has been shown, in yeast invertase to be important for the catalytic mechanism [<cite idref="PUB00002555"/>]. </p> Glycoside hydrolase, family 32, active site