Synthesis and biological effect of an anorectic peptide CART (cocaine- and amphetamine-regulated transcript) (human55-102) analogue

[Phe(4F)(97)]CART55-102 was synthesized by a solid-phase method. Hydrogen fluoride was used to deprotect and cleave the peptide from the resin except for Acm groups and a Met(0) residue. The product was treated with dithiothreitol to remove a sulfoxide group of Met(0) residue and then treated with Hg(OAc)(2) in 50% aqueous AcOH to remove Acm groups. The reduced peptide was subjected to oxidative folding to form disulfide bridges. The crude product was purified by PR-HPLC. The synthetic [Phe(4F)(97)]CART55-102 and CART55-102 were tested for comparative effect on inhibitory food intake in rats. This peptide exhibited far stronger inhibitory effect than that of the synthetic CART55-102 Abbreviations used: CART, cocaine- and amphetamine-regulated transcript; Acm, acetamidomethyl; Tos, p-toluenesulfonyl; Boc, tert-butoxycarbonyl; OBzl, benzyl ester; Z, benzyloxycarbonyl; Bzl, benzyl; ONp, p-nitrophenyl ester; RP-HPLC, reversed phase high-performance liquid chromatography; TFA, trifluoroacetic acid; EDTA, ethylenediaminetetraacetic acid; DMF, dimethylformamide; HOBT, 1-hydroxybenzotraizole; WSCI, water-soluble carbodiimide; MALDI-TOF MS, matrix-assisted laser desorption mass spectrometry; HF, hydrogen fluoride; DMSO, dimethylsulfoxide; NPY, neuropeptide Y; PBS, phosphate- buffered saline; Cl(2)Bzl, 2,6-dichlorobenzyl ether; Et3N, triethylamine.