. . . . . "L-tyrosyl-L-prolyl-L-tryptophyl-L-threonine" . . . . . . . . "Hemorphin-4" . . . . "(2S,3R)-2-(2S)-2-[[(2S)-1-[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]pyrrolidine-2-carbonyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]-3-hydroxybutanoic acid" . . . "hemorphin-4" . . . . "Hemorphin-4" . .