Patent ID: 8546072

Claim:
A peptide derivative represented by formula (1): X-A 1 -Gly-Arg-Gly-E-D (1) wherein X represents an N-terminal protecting group of amino acid, A 1 represents a leucine residue, isoleucine residue, serine residue, or threonine residue, Gly represents a glycine residue, Arg represents an arginine residue, D represents a fluorescent dye comprising a functional group, and E represents a binding arm or a spacer which is derived from a compound represented by formula (3): R 1 -A-R 2 (3) wherein R 1 represents a group having reactivity with a carboxyl group, A represents a straight-chain alkylene group having 1 to 6 carbon atoms, and R 2 represents a group having reactivity with the functional group present in the fluorescent dye represented by D.