Give some instances of basic peptides that are physiologically active.

Consider the peptides below.

How do D-amino acids differ from L-amino acids and what are the biological roles that are played by peptides that have the D-amino acids?

If you were to design a small peptide with a large net positive charge at physiological pH, which amino acid residues should predominate?

Under what conditions can a single binding site have a chemical specificity for more than one type of ligand?

None

Consider a short peptide with the sequence M-C-Q-L-Y-P-E-D-K. List the ionizable groups in this peptide, and the net charge of the whole peptide at pH a) 1.5, b) 7.0, and c)12.0.

Draw the structure of peptides TGPNLHGLFGR and ELAGAPPEPA, and calculate m/z values of their an, bn, and yn sequence ions.

(1) Discuss the structure and function of ion channels and describe their importance in medicinal chemistry. (ii) Draw the molecular structure of tamoxifen and discuss, in detail, its mode of therapeutic activity. Use the protein databank (PDB entry: 3ERT) to help support your answer.