DEHYDROOLIGOPEPTIDES .18. ENZYMATIC-HYDROLYSIS AND COUPLING OF DEHYDRODIPEPTIDE ESTERS CONTAINING ALPHA-DEHYDROAMINO ACID RESIDUE BY USING PAPAIN

The enzymatic hydrolysis of N-protected dehydrodipeptide methyl esters (2) (Protect-Delta AA-AA-OMe) was first achieved, despite the requisi te of the only neutral and large proteinic L-alpha-amino acid (AA) in the case using papain. Furthermore, the reverse enzymatic coupling of the C-component 2 with N-component alpha-amino acid anilides or dehydr odipeptide esters containing dehydrovaline (Delta Val) residue was als o successful. Consequently, the present study suggests that the proteo lytic enzyme papain is able to become a very useful tool for peptide s ynthesis by a coupling of the C-component dehydropeptide with N-compon ent alpha-amino acid, peptide, or dehydropeptide.