Abstract To analyse the role of post-translational phosphorylation and sulfation of tyrosine in peptides and proteins, we recently synthesized the new amino acids, p (CH 2 PO 3 H 2) Phe and p (CH 2 SO 3 H) Phe (D, L mixtures) as chemically and enzymatically stable analogs of (O-phospho) and (O-sulfo)-tyrosine. Here, we report improved syntheses of these amino acids and of their N-Boc protected derivatives for use in solid-phase peptide synthesis. A ...
