propioxatin B Propioxantin B 1-[(R)-2-[2-(Hydroxyamino)-2-oxoethyl]-4-methyl-1-oxopentyl]-L-Pro-L-Val-OH N-[1-[(R)-2-[2-(Hydroxyamino)-2-oxoethyl]-4-methyl-1-oxopentyl]-L-prolyl]-L-valine L-Valine, 1-[(2R)-2-[2-(hydroxyamino)-2-oxoethyl]-4-methyl-1-oxopentyl]-L-prolyl- (9CI)