Effect of 0-Alkylated Analogues of Lysine Vasopressin on Adenylate Cyclase of Pig Kidney Membranes

Abstract

O-alkylated analogues (ethyl, propyl, butyl, tert.-butyl) of lysine vasopressin (LVP) and deamino-LVP are partial agonists to LVP in their effect upon activation of adenylate cyclase in porcine kidney membranes. Emax and pD2 values are linearly dependent and both of them are inversely proportional to the overall hydrophobicity of the peptides, expressed in terms of capacity factors in reversed phase high performance liquid chromatography. It is suggested that the increasing hydrophobicity augments the tendency to either a “wrong way” binding, or to a side-side interaction of several peptide ligands bound to a multi-subsite receptor, or both. The data circumstantially indicate that the relation between the peptide-receptor interaction and cyclase activation is not a linear one.