The ability of chiral MAP fingerprints to perceive peptide stereoisomers was also well illustrated by their ability to distinguish all 512 stereoisomers of the cell-penetrating peptide nonaarginine (8), as well as the 4096 stereoisomers of polymyxin B2 (1), used as last resort antibiotic against multidrug resistant bacteria. In the latter case, our fingerprints also distinguished between the 1,512 possible sequence-scrambled isomers of 1, the 774,144 possible sequence-scrambled stereoisomers of 1, as well as between the 531,441 possible assignments of chirality as R, S, or undefined stereochemistry in the 12 chiral centers of 1. An undefined stereochemistry corresponds to a stereorandomized position accessible by chemical synthesis using a racemic amino acid at that position (stereorandomization at multiple position can lead to partially active analogs as reported for 1). In all of these cases, APC and ECFPCs were unable to distinguish all possibilities.