A New, Potent Urotensin II Receptor Peptide Agonist Containing a Pen Residue at the Disulfide Bridge

Replacing Cys(5) by Pen (penicillamine, beta,beta-dimethylcysteine) in the cyclic C-terminal U-II octapeptide, U-II(4-11), we have obtained a potent urotensin II (U-II) receptor agonist. Conformational analysis of solution NMR data indicated that the putative biologically active conformation of U-II is stabilized by introduction of a Pen residue. To the best of our knowledge, this is the most potent U-II receptor agonist reported to date.