Self-association and solubility of peptides: Solvent-titration study of Nα-protected C-terminal sequences of substance P

✍ Scribed by Claudio Toniolo; Gian Maria Bonora; George Stavropoulos; Paul Cordopatis; Dimitrios Theodoropoulos

• Publisher: Wiley (John Wiley & Sons)
• Year: 1986
• Tongue: English
• Weight: 471 KB
• Volume: 25
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360250209

✦ Synopsis

Self-association of Na-protected peptides related to Cterminal sequences of substance P in methylene chloride was disrupted by adding increasing amounts of various polar organic solvents. This process was monitored by the disappearance of the amide I C=O stretching band (1630 cm-I ) of strongly intermolecularly H-bonded molecules in the irabsorption spectra. The effects induced by mainchain length, incorporation at position 9 of a residue promoting folding (a-aminoisobutyric acid), the nature of solvent, and peptide concentration were established. A corollary IH-nmr investigation provided detailed information on the NH protons involved in the self-association process as Hbonding donors. The increasing propensity to aggregate exhibited by these peptides is paralleled by a decrease in their solubility. The impact of these results on the synthesis of substance P short sequences is briefly outlined. 'This is part 136 of the Linear Oligopeptides series. For part 135, see Bismara, C.,