Glycogen contains phosphodiester groups that can be introduced by UDPglucose: glycogen glucose 1-phosphotransferase.
Rabbit-muscle glycogen contains covalently bound phosphorus, equivalent to 1 phosphate group per 208 glucose residues. This often disputed, minor component was previously thought to represent a phosphomonoester group at C-6 of a glucose residue. Here we show that more than half the phosphorus is present as a phosphodiester, the remainder being monoester. A novel enzyme activity has been found in muscle that can account for the presence of the phosphodiester in glycogen. This is a UDPglucose: glycogen glucose 1-phosphotransferase that positions glucose 1-phosphate on C-6 of glucose residues in glycogen, forming a diester. The phosphomonoester groups present may arise by removal of the glucose residue originally transferred as glucose 1-phosphate.
Department of Biochemistry and Molecular Biology, University of Miami, FL 33101.
J
J
Lomako
W M
WM
Lomako
W J
WJ
Whelan
R B
RB
Marchase
D000818:Animals; D004952:Esters / Q000378:metabolism; D006003:Glycogen / Q000737:chemistry / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology* / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism*; D011817:Rabbits; D017855:Transferases (Other Substituted Phosphate Groups)
D004952:Esters; D009943:Organophosphorus Compounds; D006003:Glycogen; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C082940:UDPglucose-glycogen glucose 1-phosphotransferase