1. Synthesis of N(alpha)-Boc-N(epsilon)-tetrabenzyl-DTPA-L-lysine and N(alpha)-Fmoc-N(epsilon)-tetra-t-butyl-DTPA-L-lysine, building blocks for solid phase synthesis of DTPA-containing peptides
John S Davies, Loai Al-Jamri J Pept Sci. 2002 Dec;8(12):663-70. doi: 10.1002/psc.427.
Two building blocks, Boc-Lys(Bn4-DTPA)-OH and Fmoc-Lys(Bu4(t)-DTPA)-OH have been synthesized via the acylation of the epsilon-amino group of N(alpha)-protected lysine, using suitably protected tetra-esters of diethylene triamine pentaacetic acid (DTPA), a ligand with wide application as a chelating agent for complexing metal tons to peptides.
2. Synthesis and biological activity of homoarginine-containing opioid peptides
Jan Izdebski, Danuta Kunce, Peter W Schiller, Nga N Chung, Tomasz Gers, Monika Zelman, Monika Grabek J Pept Sci. 2007 Jan;13(1):27-30. doi: 10.1002/psc.785.
Two tris-alkoxycarbonyl homoarginine derivatives, Boc-Har{omega,omega'-[Z(2Br)]2}-OH and Boc-Har{omega,omega'-[Z(2Cl)]2}-OH, were prepared by guanidinylation of Boc-Lys-OH, and used for the synthesis of neo-endorphins and dynorphins. The results were compared with that obtained in the synthesis in which Boc-Lys(Fmoc)-OH was incorporated into the peptide chain, and after removing Fmoc protection, the resulting peptide-resin was guanidinylated with N,N'-[Z(2Br)]2- or N,N'-[Z(2Cl)]2-S-methylisourea. The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. The results indicated that replacement of Arg by Har may be a good avenue for the design of biologically active peptides with increased resistance to degradation by trypsin-like enzymes.
