the substances tested were : ( 8a ) n-acetylmuramyldipeptide ( mdp ) and the following derivatives thereof : mdp modified in positions c3 and c4 , or with l-alanine substituted by l-2-aminobutyric acid or with the peptide chain prolonged ( by three lysines or a polylysine ) ;
C0024337
lysines
C0032518
polylysine