sentences:  It is an undecapeptide with the amino acid sequence Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2.SP binds to all three of the tachykinin receptors, but it binds most strongly to the NK1 receptor.Tachykinin NK1 receptor, often referred to as NK1 receptor, is a member of family 1 (rhodopsin-like) of G protein-coupled receptors and binds to the Gαq protein.