where is glycogen stored when not needed for immediate energy
Glycogen
Glycogen synthesis is , unlike its breakdown , endergonic -- it requires the input of energy . Energy for glycogen synthesis comes from uridine triphosphate ( UTP ) , which reacts with glucose - 1 - phosphate , forming UDP - glucose , in a reaction catalysed by UTP -- glucose - 1 - phosphate uridylyltransferase . Glycogen is synthesized from monomers of UDP - glucose initially by the protein glycogenin , which has two tyrosine anchors for the reducing end of glycogen , since glycogenin is a homodimer . After about eight glucose molecules have been added to a tyrosine residue , the enzyme glycogen synthase progressively lengthens the glycogen chain using UDP - glucose , adding α ( 1 → 4 ) - bonded glucose . The glycogen branching enzyme catalyzes the transfer of a terminal fragment of six or seven glucose residues from a nonreducing end to the C - 6 hydroxyl group of a glucose residue deeper into the interior of the glycogen molecule . The branching enzyme can act upon only a branch having at least 11 residues , and the enzyme may transfer to the same glucose chain or adjacent glucose chains .
Glycogen synthesis is , unlike its breakdown , endergonic -- it requires the input of energy . Energy for glycogen synthesis comes from uridine triphosphate ( UTP ) , which reacts with glucose - 1 - phosphate , forming UDP - glucose , in a reaction catalysed by UTP -- glucose - 1 - phosphate uridylyltransferase . Glycogen is synthesized from monomers of UDP - glucose initially by the protein glycogenin , which has two tyrosine anchors for the reducing end of glycogen , since glycogenin is a homodimer . After about eight glucose molecules have been added to a tyrosine residue , the enzyme glycogen synthase progressively lengthens the glycogen chain using UDP - glucose , adding α ( 1 → 4 ) - bonded glucose . The glycogen branching enzyme catalyzes the transfer of a terminal fragment of six or seven glucose residues from a nonreducing end to the C - 6 hydroxyl group of a glucose residue deeper into the interior of the glycogen molecule . The branching enzyme can act upon only a branch having at least 11 residues , and the enzyme may transfer to the same glucose chain or adjacent glucose chains .