Total solid-phase synthesis of bombesin analogs with different functional groups at the C-terminus.
Five bombesin analogs with different functional groups at the C-terminus were synthesized using a solid-phase strategy. The protocols were optimized using 4-(hydroxymethyl)benzoic acid (HMBA) resin to synthesize a common precursor followed by nucleophilic cleavage of the base sensitive peptide ester linkage. The C-terminal modifications included ethylamide, butylamide, methyl ester, propyl ester and hydrazide. Cleavage from the resin was possible with the fully protected or deprotected precursor peptide; however, higher purity of the final products was achieved when cleavage protocols were conducted after side-chain deprotection. The synthesized peptides were analyzed and characterized using reverse phase HPLC and ESI-MS. The peptides were obtained in 13-32% overall recovery, calculated from the coupling efficiency of the first amino acid residue, and in 91-97% purity.
Abd-Elgaliel
Wael R
WR
Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
Gallazzi
Fabio
F
Lever
Susan Z
SZ
D001839:Bombesin / Q000031:analogs & derivatives* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D010455:Peptides; D001839:Bombesin