- Eledoisin
Eledoisin is an undecapeptide of
mollusk origin, it is a member of thetachykinin family ofneuropeptides . It has a molecular formula of C54H85N13O15S and a molecular weight of 1188.4.1It was first isolated from the posterior
salivary gland s of two mollusk speciesEledone muschata and Eledone aldovandi which belong to theoctopod order ofCephalopoda (De Marco & Gatti).2Other tachykinins from nonmammalian sources include
kassinin andphysalaemin . The mammalian tachykininssubstance P , NKA, and NKB have similar effects as tachykinins of nonmammals and have been more widely studied and characterized. These peptides exhibit a wide and complex spectrum of pharmacological and physiological activities such asvasodilation ,hypertension , and stimulation of extravascularsmooth muscle .2Eledoisin has the
amino acid sequence pGlu-Pro-Ser-Lys-Asp-Ala-Phe-Ile-Gly-Leu-Met-NH2. Like all tachykinin peptides, Eledoisin shares the same consensus C-terminal sequence, that is, Phe-Xxx-Gly-Leu-Met-NH2. The invariant "Phe7" residue is probably required for receptor binding. "Xxx" is either an aromatic (phenylalanine, tyrosine) or a branched aliphatic (valine, isoleucine) side chain and is thought to be important in receptor selectivity. This common region, often referred to as the "message domain," is believed to be responsible for activating the receptor. The divergent N-terminal region or the "address domain" varies in amino-acid sequence and length and is believed to play a role in determining the receptor subtype specificity (Schwyzer, 1987).2References
1. www.prospecbio.com/english/Product.aspx?Product=664&Category=11, Retrieved 05 Dec 2007
A commercial supplier of purified eledoisin2. R. Christy Rani Grace, Indu R. Chandrashekar and Sudha M. Cowsik, Solution Structure of the Tachykinin Peptide Eledoisin, Biophysical Journal 84:655-664 (2003) (www.biophysj.org/cgi/content/full/84/1/655, Retrieved 05 Dec 2007)
(This publication has excellent general information on the eledoisin molecule.)3. De Marco, A., and G. Gatti, 1H- and 13C-NMR spectra of eledoisin and intermediate oligopeptides. Int. J. Pep. Pro. Res. 7:437–444, 1975
4. Schwyzer, R., Membrane-assisted molecular mechanism of neurokinin receptor subtype selection. EMBO J. 6:2255–2259, 1987
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