51724-57-3 55476-91-0 L-Valinamide, N-(2-methyl-1-oxopropyl)-L-valyl-N-(4-((2-((1-(2-carboxy-1-hydroxyethyl)-3-methylbutyl)amino)-1-methyl-2-oxoethyl)amino)-2-hydroxy-1-(2-methylpropyl)-4-oxobutyl)-, (1S-(1R*,2R*,4(R*(R*(R*)))))- N-Isobutyrylpepstatin Pepsinostreptin