Sulfoquinovose is rarely found in its free form in nature; rather it occurs predominantly as a glycoside, SQDG. SQDG can be deacylated to form lyso-SQDG and sulfoquinovosylglycerol (SQGro). Sulfoquinovose is obtained from SQ glycosides by the action of sulfoquinovosidases, which are glycoside hydrolases that can hydrolyse the glycosidic linkage in SQDG, or its deacylated form, sulfoquinovosyl glycerol (SQGro).
There are two main classes of sulfoquinovosidases. The first are classical glycoside hydrolases (which belong to CAZy family GH31), and is exemplified by the sulfoquinovosidase YihQ from Escherichia coli. Family GH31 sulfoquinovosidases cleave SQ glycosides with retention of configuration, initially forming α-sulfoquinovose. YihQ sulfoquinovosidase exhibits a preference for the naturally occurring 2’R-SQGro. The second class of sulfoquinovosidases are NAD-dependent enzymes (which belong to CAZy family GH188) that use an oxidoreductive mechanism to cleave both α- and β-glycosides of sulfoquinovose.
Sulfoglycolysis encoding operons often contain gene sequences encoding aldose-1-epimerases that act as sulfoquinovose mutarotases, catalyzing the interconversion of the α and β anomers of sulfoquinovose.