The molecule is an oligopeptide comprising of nine amino acids with sequence L-Ile-L-Ala-L-Arg-L-Arg-L-His-L-Pro-L-Tyr-L-Phe-L-Leu. It was originally isolated from pepsin-treated human plasma and shares some sequence homology with the C-terminal end of neurotensin. It is a potent histamine releaser and may serve as an inflammatory mediator. It has a role as a human metabolite and a histamine releasing agent. It is a conjugate base of a kinetensin(2+).
(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S,3S)-2-amino-3-methylpentanoyl]amino]propanoyl]amino]-5-(diaminomethylideneamino)pentanoyl]amino]-5-(diaminomethylideneamino)pentanoyl]amino]-3-(1H-imidazol-5-yl)propanoyl]pyrrolidine-2-carbonyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoic acid