7. The amino acid proline has a structure that is unusual among amino acids. Compare the general structure of an amino acid with that of proline

Question

7. The amino acid proline has a structure that is unusual among amino acids. Compare the general structure of an amino acid with that of proline, shown here:

COO- H2N C H

H2C CH2 CH2

What is the major difference between proline and the other amino acids? Draw the structure of a dipeptide in which the amino group of proline forms a peptide bond with the carboxyl group of alanine.

Answer 1

The major difference between proline and other amino acids is that the alpha amino group in proline is actually part of a 5-membered ring whereas the alpha amino group in most other amino acids is part of a straight chain.

I can't draw the condensation between proline and alanine but since alanine is HOOC-CH(NH2)-CH3, just hook the N from proline (remove the H) with the OH of the COOH from alanine to produce H2O and the amide bond.