STUDIES ON PEPTIDES. XCIV. SYNTHESIS AND ACTIVITY OF KYOTORPHIN AND ITS ANALOGS

A dipeptide named kyotorphin, H-Tyr-Arg-OH, and its retro isomer were synthesized using NG-mesitylene-2-sulfonylarginine. Two corresponding stereoisomers containing D-Arg were also synthesized. Among these, H-Tyr-D-Arg-OH was found to possess an analgesic effect 6 times higher than that of the corresponding L-isomer.