Secondary structure characteristics of proenkephalin peptides E, B, and F.

The conformations of three adrenal medullary enkephalin containing polypeptides (ECPs) were investigated to gain an understanding of their potential structure-activity relationships. Secondary structure characteristics of peptides E, B, and F were examined by circular dichrosim (CD) under conditions designed to mimic both the soluble state and the anisotropic environment which exists at the biological effector site. Conformational differences between the three peptides were further examined by Fourier Transform Infrared Spectroscopy (FTIR) and by empirical predictions for conformation and hydrophobic periodicity. Although all three peptides have a similar structure, existing in random configurations in aqueous solutions, they do exhibit unique individual potentials to assume secondary structure in less polar environments. These conformational differences may be important factors in determining their unique individual biological activities.