Synthetic peptides related to laminin pentapeptide (YIGSR) fragment.

The synthetic laminin pentapeptide amide fragment (LF), Tyr-Ile-Gly-Ser-Arg-NH2 corresponding to a part of B1 chain of the glycoprotein, laminin, and six of its analogues having structural modifications at positions 1, 3 and 4 were synthesized by solid phase method employing mainly 9-fluorenylmethoxycarbonyl-amino acid trichlorophenyl esters as coupling agents and Merrifield resin as the solid support. Their biological activities were studied in vivo by lung tumor colonization assay and in vitro by cell adhesion assay. The activity of synthetic LF was found to correlate with the earlier reported results in both in vivo and in vitro assays. Among the analogues made, [Tyr4] LF and [Thr4]LF were found to inhibit the lung tumor colonies more efficiently than LF itself in the in vivo assay whereas [D- Ser4]LF exhibited almost the same inhibition as LF.

Synthetic peptides related to the delta-receptor agonist, dermorphin gene associated peptide.

The delta-receptor selective dermorphin gen associated peptide (DGAP) and five of its analogues having structural modifications at positions 2, 4 and 5 were synthesized by the solid phase method using 9-fluorenylmethoxycarbonyl amino acid trichlorophenyl esters as coupling agents and rho-benzyloxybenzyl alcohol resin as the solid support. The delta-receptor selectivity of these peptides was determined by guinea pig ileum and mouse vas deferens assays. The latter assay was carried out using modified Kreb's solution aerated with pure oxygen instead of carbogen. All the synthetic peptides were found to be delta-receptor selective.

Improved solid phase synthesis of luteinizing hormone releasing hormone analogues using 9-fluorenylmethyloxycarbonyl amino acid active esters and catalytic transfer hydrogenation with minimal sidechain protection and their biological activities.

Using mainly 9-fluorenylmethyloxycarbonyl amino acid 2, 4, 5-trichlorophenyl esters in the presence of 1-hydroxybenzotriazole and the solid support p-alkoxybenzyl alcohol resin, synthesis of luteinizing hormone releasing hormone analogues was carried out with minimal side-chain protection. Catalytic transfer hydrogenation was employed for removal of NO2 and Z-groups from Arg and < Glu respectively avoiding the use of HF and this led to good yields. An aromatic, hydrophilic amino acid, D-(p-hydroxyphenyl) glycine was incorporated into luteinizing hormone releasing hormone molecule along with other modifications. The agonistic as well as antagonistic activities of all the peptides have been studied.