Structure — Function of LH-RH Analogs and Design Applications to other Peptide Systems

Abstract

It is probable that more synthetic analogs of LH-RH have been made than any other peptide. This considerable research effort, carried out by many groups over a 12 year period since the initial sequencing of the LH-RH decapeptide by Matsuo et al. (1971), has been aimed at the development of increasingly more active competitive antagonists. In the process, the research has provided a tremendous stimulus for improvement of rapid peptide synthesis techniques and general strategies for the speedy development of improved analogs of other peptides. Events leading to the discovery of weak LH-RH antagonists followed by their steady improvement have been frequently reviewed (see for instance, Coy et al. (1981) and Schally et al. (1981). Of tremendous importance to this process was the discovery of the LH-RH superagonist series which was based on the presence of D-amino acids, particularly those with large, aromatic side-chains in place of glycine in position 6 (Monahan et al., 1976; Coy et al., 1976). The increased rigidity and stabilization of the preferred receptor binding conformation produced by D-amino acids has been further utilized in many other positions of the antagonist sequences. The D-amino acid substitution strategy has also become perhaps the prime design approach in many other peptide systems and has yielded many impressive results of late.