Question

A .200g sample of amylopectin was analyzed to determine the fraction of the total glucose residue that are branch points in the structure. The structure was exhaustively methylated and then acid digested, yielding 50.0 umoles of the reducing ends.

a. What other products, and in what umolar amounts, were obtained?

b. What fraction of the total residues are branch points in the amylopectin sample?

c. How many reducing ends does each amylopectin molecule have?

d. How many nonreducing ends does the average amylopectin molecule in this sample have?

e. What is the average molecular weight of the amylopectin molecule in this sample?

f. What is the average number of residues per branch for the average amylopectin molecule in this sample?

Answer 1

amylopectin is a compound having many glucose molecule having variable molecular wt., if the structure is exhaustively methylated, the all the hydroxyl groups gets methylated by replacing hydrogen atom from oxygen atom, and after digesion with acid it gives 2,3-Di-Omethyl glucose .

a. 2,3-Di-Omethyl glucose

b

c. amylopectin has only one reducing end.

d. there are many non reucing ends in amylopectin molecule.

e. average number of residue per branch for average amylopectin is one.

f