69221-84-7 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)), ((S),(S),(S))- Poly(val-pro-gly-val-gly) Poly(vpgvg) Valyl-prolyl-glycyl-valyl-glycine polypeptide