| abstract |
A peptide derivative represented by Formula (I) or a pharmaceutically acceptable salt thereof: n n n n n n n n n n wherein X represents an oxygen atom or NR, Y represents NH 2 , N(Me)H, SH, OH, or phenyl in which any one of hydrogen atoms is replaced by NH 2 or OH, and R represents a hydrogen atom or C 1 -C 3 alkyl, provided that the derivative where X is NH, and Y is NH 2 , and the derivative where X is NH, and Y is N(Me)H are excluded. |