This family of glycosyl hydrolases contains vacuolar acid trehalase and maltose phosphorylase.Maltose phosphorylase (MP) is a dimeric enzyme that catalyses the conversion of maltose and inorganic phosphate into beta-D-glucose-1-phosphate and glucose. The C-terminal domain forms a two layered jelly roll motif. This domain is situated at the base of the catalytic domain, however its function remains unknown [1].

1: Crystal structure of maltose phosphorylase from Lactobacillus brevis: unexpected evolutionary relationship with glucoamylases. Egloff MP, Uppenberg J, Haalck L, van Tilbeurgh H; Structure (Camb) 2001;9:689-697. PMID:11587643