| abstract |
Disclosed herein is an azo dye compound having a structural unit represented by the following formula in its molecule: -X-Y-(R1)(R2)(R3)k [I] wherein Y is a 6-membered ring containing 2 or 3 nitrogen atoms, X is a linking group for bonding a main body of the dye molecule to Y, R1 is the first amino acid residue, R2 is an atomic group selected from the following group A, R3 is another atomic group selected from the following group B, and k is a number of 0 or 1: Group A: H, OH, NH2, CN, =O and the second amino acid residue; Group B: H, OH, NH2, CN and =O, the first and second amino acid residues being identical with or different from each other. <IMAGE> |