Soluble quinoprotein glucose/sorbosone dehydrogenase <p>Quinoproteins form a class of dehydrogenases distinct from the NAD(P)- and flavin-dependent enzymes, using one of four different quinone cofactors for the oxidation of a variety of compounds. Soluble glucose dehydrogenase (s-GDH) from the bacterium <taxon tax_id="471">Acinetobacter calcoaceticus</taxon> is a quinoprotein that requires the cofactor pyrroloquinoline quinone (PQQ) to catalyse the oxidation of glucose to gluconolactone [<cite idref="PUB00014148"/>]. s-GDH has six 4-stranded beta-sheets in a beta-propeller fold.</p>