STUDIES ON THE MODIFICATION OF ARGININE, LYSINE AND TRYPTOPHAN RESIDUES IN CECROPIN D FROM THE CHINESE OAK SILK MOTH, ANTHERAEA PERNYI
柞蚕抗菌肽D中精氨酸、赖氨酸和色氨酸等氨基酸残基的化学修饰

The tryptophan, arginine and lysinc residues of cecropin D were modified by N-bromosuccinimide (NBS), 1, 2 -cyclohexanedione ( CHD ) and maleic anhydride (MLH) respectively. It was found that the tryptophan residue bore little relationship to the antibacterial activity of the peptide against Escherichia coli D31, but that the arginine and lysine residues were important to the antibacterial activity. The modification of the arginine or lysine residue of cecropin D resulted in a total loss of its antibacterial activity against E. coli D31. When the arginine and lysine residues were each regenerated from the modified structures the antibacterial aciivity of cecropin D was recovered. These results suggest that the antibacterial activity of cecropin D is related to the charge in the molecule. Ouchterlony double immunodiffusion showed that the antigenic determinant of cecropin D is closely connected with the arginine residues in the peptide.