a) Describe the isoelectric point. With the help of an example explain the utility of this
property of amino acids and how it is useful in maintaining pH in human systems.
a) Define disaccharides. Write structures for disaccharides in which glucose units are linked
together in the following ways.
i) - 1,4 ii) - 1,4 iii) - 1,6 iv) - 1,6
3) Draw the complete structures of the following amino acid or oligopeptide.
a. The dipeptide Ala-His
b. The tripeptide Glu-Pro-Cys
4) Re-write the following peptides using the three letter amino acid codes. a. HEWATRGIR
b. QYKVLMCD
5) Draw the predominate form(s) of histidine at the following pH values. a. pH 3.0
b. pH 8.0 c. pH 10.0
6) Indicate whether and where the following peptides are cleaved by the indicated treatments.
Peptide
a. Phe-Arg-Pro b. Phe-Met-Leu c. Ala-Gly-Phe d. Gly-Met-Pro e. Pro-Arg-Met
Treatment
trypsin carboxypeptidase B chymotrypsin CNBr
trypsin
7) Consider the peptide: YHFDMPTKQERGNPCVDRPIASMVLIMEALIKYAGAELICSHWNWDEA a. If it is cleaved with trypsin, what are the sequences of the fragments?
b. If it is cleaved with pepsin, what are the sequences of the fragments?
Describe the isoelectric point.With the help of an example explain the utility of this property of amino acids and how it is useful in maintaining pH in human systems.