The 2,4-dinitrophenyl group for protection of hydroxyl function of tyrosine during solid-phase peptide synthesis.

The facile thiolytic cleavage of the O-2,4-dinitrophenyl (Dnp) tyrosine bound was applied to the solid-phase synthesis of the 22-amino acid residue peptide H-Asp-Ala-Val-Tyr-Thr-Gly-Leu-Asn-Thr-Arg-Asn-Gln-Glu-Thr-Tyr-Glu-Thr-Le u-Lys- His-Glu-Lys-OH, corresponding to positions 62-83 in the chain of the type 1 receptor for Fc epsilon domains expressed on the rat mucosal-type mast cells (line RBL-2H3). A method for the spectrophotometric determination of insoluble O-Dnp as well as of unprotected phenolic moieties of tyrosine was developed. It is based on monitoring S-Dnp-2-mercaptoethanol, produced upon O-Dnp thiolysis by 2-mercaptoethanol.