Collect. Czech. Chem. Commun. 1988, 53, 1579-1605

Polarography of the oxytocin and vasopressin synthetic analogs

Pavel Madera, Věra Veseláb, Michael Heyrovskýc, Michal Lebld and Milena Braunsteinováe

a Faculty of Agronomy, University of Agriculture, 165 21 Prague 6-Suchdol
b Institute of Experimental Physics, Slovak Academy of Sciences, 043 53 Košice
c The J. Heyrovský Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, 118 40 Prague 1
d Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6
e Léčiva, n.p., závod 04, 180 47 Prague 9


Small changes in the molecules of the oxytocin and vasopressin synthetic analogs bring about considerable changes in their polarographic behaviour within the entire potential interval available (+0·5 to -2·0 V VS SCE). In the study of the polarographic activity of ten peptides we used classical, differential pulse and alternating current polarography and cyclic voltammetry. Liquid chromatographic separation studies of the peptides on the reverse phase complemented the electrochemical investigation. Hydrophobicity showed to be the parameter which decisively influences the polarographic behaviour of the studied peptides. Strong interaction of the SS and S-carba analogs with the electrode material (mercury) has been observed and surface activity of the SH-forms of the peptides at negative potentials has been confirmed. The importance of various functional groups in the peptide molecule for the catalytic activity in hydrogen evolution at negative potentials is discussed.