A pioneer synthesis of conjugates of a thymic peptide hormone and polyamines.

To synthesize peptidic derivatives of polyamines, sequential reactions were designed for the polyfunctional peptides and polyfunctional amines which utilize specific protection and deprotection. Utilizing these reactions, a thymic nonapeptide, a lymphocyte-differentiating hormone, was coupled with spermidine and spermine to yield, respectively: Glp-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-NH(CH2)3NH(CH2)4NH2; Glp-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-NH(CH2)3NH-(CH2)4NH(CH2) 3NH2. Both conjugates inhibited rather than stimulated incorporation of [3H]-thymidine into DNA at levels 20-fold that of spermine. This activity is less than that based on the percent of the spermine moeity (ca. 20%) in the conjugate.