Synthesis of sequential polypeptides containing lysine and tyrosine

Sequential polypeptides with the repeating units L ‐tyrosyl‐ L ‐lysyl, L ‐tyrosyl‐( L ‐lysyl) 2 , and L ‐tyrosyl‐( L ‐lysyl) 3 have been synthesized by solution polymerization of the N ‐hydroxy‐succinimide esters of the corresponding di‐, tri‐, and tetrapeptides. The monomers for the polytripeptide and polytetrapeptide were prepared by fragment condensation, using the mixed carbonic anhydride coupoling method. Moderately high molecular weight polypeptides were obtained.