Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase

UniProtKB accession:  P9WQ16

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Essential maltosyltransferase that uses maltose 1-phosphate (M1P) as the sugar donor to elongate linear or branched alpha-(1->4)-glucans. Maltooligosaccharides with a degree of polymerization (DP) superior or equal to 4 are efficient acceptors, with DP5 being optimal in the GlgE-catalyzed polymerization with M1P. Is specific for the alpha-anomer of M1P as substrate, since the beta-anomer of M1P gives no activity. Exhibits an alpha-retaining catalytic mechanism. Is also able to catalyze the reverse reaction in vitro, releasing M1P from glycogen in the presence of inorganic phosphate. Also catalyzes disproportionation reactions through maltosyl transfer between maltooligosaccharides. Is involved in a branched alpha-glucan biosynthetic pathway from trehalose, together with TreS, Mak and GlgB (By similarity).