title: beta-Endorphin. Circular dichroism of synthetic human analogs with various chain lengths in methanol solutions.
abstract: The alpha-helix content of human beta-endorphin (beta h-EP) has been determined by circular dichroism (CD) in solutions ranging from 0 to 95% methanol in water. In addition, the CD spectra of beta h-EP-(1-30),-(1-29),-(1-28),-(1-27),-(1-26),-(1-21) and -(1-15) have been examined in 90% methanol, and their alpha-helix contents estimated using parameters determined for this solvent. Addition of methanol to beta h-EP solutions brings about a noncooperative formation of alpha-helix. An attempt to correlate secondary structure in methanol with biological and immunological activities showed limited direct correspondence, but may indicate the involvement of the tertiary interactions.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D004723:Endorphins / Q000494:pharmacology; D006168:Guinea Pigs; D000432:Methanol; D051379:Mice; D011487:Protein Conformation; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin; D000432:Methanol