試題詳解

44. Which of the following statements about glycogen synthesis is incorrect?
(A) The initiation of glycogen synthesis is the attachment of the first glucose to the OH group of a tyrosine on a protein named glycogenin.
(B) A chain of about seven c(1→4) linked glucose molecules are typically formed by glycogenin.
(C) Glycogen synthase uses UDP-glucose as a substrate and transfers the glucosyl residue onto the non-reducing end of the glycogen chain.
(D) Branches of glycogen are made by an amylo-transglycosylase that catalyzes the transfer of a string of seven a(1→4) linked glucosyl units of a glycogen chain to the C-2 position on a glucose of the same or a neighboring glycogen chain.
(E) UDP-glucose is synthesized from UTP and glucose-I-phosphate by enzyme glucose-1-phosphate uridylyltransferase.