Use of the Npys thiol protection in solid phase peptide synthesis. Application to direct peptide-protein conjugation through cysteine residues.
The protection of the thiol function of cysteine with the 3-nitro-2-pyridylsulfenyl (Npys) group has been successfully applied in the solid phase synthesis of nine peptides. A reexamination of the chemical stability of the protecting group has shown that, while Npys is essentially suitable for standard Boc/benzyl synthesis conditions, it is inadequate for the Fmoc strategy. Its proven stability to "high" HF acidolysis can not be extended to "low-high" conditions without significant thiol deprotection. On the other hand, the Npys group is quite compatible with standard photolytical cleavage conditions. The stability of Npys to HF and its thiol-activating character allow its application in peptide-carrier protein conjugation reactions by specific coupling through cysteine residues in the peptide.
Albericio
F
F
Department of Organic Chemistry, University of Barcelona, Spain.
Andreu
D
D
Giralt
E
E
Navalpotro
C
C
Pedroso
E
E
Ponsati
B
B
Ruiz-Gayo
M
M
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D009574:Nitro Compounds; D010455:Peptides / Q000138:chemical synthesis*; D011725:Pyridines
D007202:Indicators and Reagents; D009574:Nitro Compounds; D010455:Peptides; D011725:Pyridines; D003545:Cysteine