The GlvG polypeptide of 212 residues cross-reacts with antibodies prepared against the full-length 6-phospho-alpha-D-glucosidase (MalH) from Fusobacterium mortiferum. This operon may be cryptic in wild-type K12 strains (Probable). Belongs to the glycosyl hydrolase 4 family. Could be the product of a pseudogene. Lacks the C-terminal half of the catalytic domain found in other members of this family. This truncated polypeptide does not display phospho-alpha- or phospho-beta-glucosidase activity (PubMed:9209025).