Purification and characterization of the hyper-glycosylated extracellular α-glucosidase from Schizosaccharomyces pombe

α-Glucosidase secreted from Schizosaccharomyces pombe cell has been purified as a homogeneous protein from culture supernatant. The α-glucosidase is hyper-glycosylated form, which included 88% of sugar components, and the relative molecular mass is calculated in 1120 kDa. Heat stability and proteolysis susceptibility of the α-glucosidase is descended by enzymatical deglycosylation. By MALDI-TOF MS analysis, seven Asn residues (Asnl85, Asn221, Asn496, Asn499, Asn572, Asn777 and Asn787; numbering from N-terminal of matured form) out of 27 potential N-glycosylation sites of the enzyme are presumed to be modified. The native form of S. pombe α-glucosidase have three subsites in the catalytic site and so prefer α-l,4-glucosidic linkage in short substrates, such as maltose and maltotriose, to longer substrate. The enzyme also acts on α-1,2, α-1,3, and α-l,6-glucosidic linkage.