Question

1 part A) The branching enzyme of glycogen synthesis _________________.

a. couples the formation of glycogen with UDP loss from UDP-glucose

b. making α(1,4) linkages with the transfer of seven glucose units

c. breaks the α(1,6) branch points and remakes α(1,4) linkages

d. catalyzes the cleavage of α(1,4) linkages and the formation of α(1,6) linkages

PART b) Which of the following conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phorphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

a. Elevated concentrations of NADH and ATP.

b. Elevated concentrations of NAD+ and ADP.

c. Elevated concentrations of Ca2+ .

d. Elevated concentrations of acetyl CoA.

Answer 1

1) Catalyzes the cleavage of α(1,4) linkages and the formation of α(1,6) linkages

   Glycogen synthase enzyme that adds activated glucose residues can only extend glycogen if the initial glycogen chain more than four glucose molecules long. Before the glycogen synthase can begin glycogen synthesis another enzyme called glycogenin must create glycogen primer. This primer is short sequence of glucose residues connected by alpha 12-4 glycosidic linkage.

2) Elevated concentrations of NADH and ATP.

Pyruvate dehydrogenase complex is located at very important locations in the scheme of overall metabolism and thus it activity is tightly regulated to direct the flow of 2 carbon acetyl unit s form glycolysis into citric acid cycle is essential because the conversion of pyruvate into acetyl coA catalyzed by pyruvate dehydrogenase complex which is done by NADH and acetyl coA and modification by phosphorylation of E1 subunit.