1-Arg-2-pro-7,9-trp-substance P 83440-04-4 Apttsp Substance P, 1-D-arginine-2-D-proline-7-D-tryptophan-9-D-tryptophan- Substance P, arg(1)-pro(2)-trp(7,9)- Substance P, arginyl(1)-prolyl(2)-tryptophan(7,9)-