1-Arg-2-pro-7,9-trp-11-leu-substance P 83374-71-4 Apttlsp Substance P, 1-D-arginine-2-D-proline-7-D-tryptophan-9-D-tryptophan-11-D-leucine Substance P, arg(1)-pro(2)-trp(7,9)-leu(11)- Substance P, arginyl(1)-prolyl(2)-tryptophyl(7,9)-leucine(11)-