56899-27-5 81857-53-6 Elastin polypentapeptide H-(Val-pro-gly-val-gly)(n)-val-ome Poly(1,2-pyrrolidinediylcarbonylimino(2-oxo-1,2-ethanediyl)imino(1-(1-methylethyl)-2-oxo-1,2-ethanediyl)imino(2-oxo-1,2-ethanediyl)imino(1-(1-methylethyl)-2-oxo-1,2-ethanediyl)), alpha-(2-amino-3-methyl-1-oxobutyl)-omega-methoxy-, (all-S)- Polypentapeptide, elastin