SOLID-PHASE SYNTHESIS OF 2 PHOSPHORYLATED PEPTIDES RELATED TO CASEIN USING ALLYL PHOSPHATE PROTECTION, AND THEIR CD SPECTRA

Phosphoserine peptides related to the casein kinase II substrate conse nsus sequence ESLSSSEE have been synthesized using N-Boc-O-diallylphos phono-L-serine by solid-phase methods. The allyl groups were removed, while the peptide was still attached to the solid support, by Pd-0 wit h azide as the nucleophile. Far UV circular dichroism measurements ind icate that peptides phosphorylated at Ser 4 or Ser 5 have a somewhat h igher content of ordered structure than the non-phosphorylated peptide .