A compound represented by formula (1-1): wherein b represents an integer of 1 to 5; and Z is a group represented by formula (Z-1), formula (Z-2), formula (Z-3), formula (Za-1), formula (Za-2), formula (Za-3), formula (Za-4) or formula (Za-5): where n represents an integer of 0 to 4, where n is an integer of 1 to 4 when Z is a group represented by formula (Za-4) or formula (Za-5); AA represents a glutamic acid residue (Glu), an aspartic acid residue (Asp) or a lysine residue (Lys), and when there is a plurality of AAs, each AA may be the same as or different from each other and AAs are bonded to each other via an amide bond; an N-terminal nitrogen atom of (AA) n forms an amide bond together with carbonyl group (a); R aa represents a C 1-6 alkyl group; Q represents a group represented by formula (Qa-1), formula (Qa-2), formula (Qa-3), formula (Qa-4), formula (Qa-5), formula (Qa-6) or formula (Qa-7): where R ab and R ac each independently represent a hydrogen atom, a halogen atom, a C 1-6 alkyl group or a C 1-6 alkoxy group; and R ad , R ae and R af each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, an amino group, a carboxyl group, a phenyl group, or a C 1-6 alkyl group, C 1-6 alkoxy group or C 1-6 alkyl ester group optionally substituted with 1 to 3 fluorine atoms; R 1a and R 1b each independently represent a hydrogen atom or a methyl group; R 2 represents -(CH 2 ) u -COR 4 ; u represents 1 or 2; R 3 and R 4 each independently represent -OH or -(AB) p ; AB represents Glu, Asp or Lys, and when there is a plurality of ABs, each AB may be the same as or different from each other and ABs are bonded to each other via an amide bond; and p represents an integer of 1 to 4; with a proviso that when R 3 or R 4 is -(AB) p , a sum of n and p is an integer of 1 to 5, or a salt thereof. b represents an integer of 1 to 5; and Z is a group represented by formula (Z-1), formula (Z-2), formula (Z-3), formula (Za-1), formula (Za-2), formula (Za-3), formula (Za-4) or formula (Za-5): where n represents an integer of 0 to 4, where n is an integer of 1 to 4 when Z is a group represented by formula (Za-4) or formula (Za-5); AA represents a glutamic acid residue (Glu), an aspartic acid residue (Asp) or a lysine residue (Lys), and when there is a plurality of AAs, each AA may be the same as or different from each other and AAs are bonded to each other via an amide bond; an N-terminal nitrogen atom of (AA) n forms an amide bond together with carbonyl group (a); R aa represents a C 1-6 alkyl group; Q represents a group represented by formula (Qa-1), formula (Qa-2), formula (Qa-3), formula (Qa-4), formula (Qa-5), formula (Qa-6) or formula (Qa-7): where R ab and R ac each independently represent a hydrogen atom, a halogen atom, a C 1-6 alkyl group or a C 1-6 alkoxy group; and R ad , R ae and R af each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, an amino group, a carboxyl group, a phenyl group, or a C 1-6 alkyl group, C 1-6 alkoxy group or C 1-6 alkyl ester group optionally substituted with 1 to 3 fluorine atoms; R 1a and R 1b each independently represent a hydrogen atom or a methyl group; R 2 represents -(CH 2 ) u -COR 4 ; u represents 1 or 2; R 3 and R 4 each independently represent -OH or -(AB) p ; AB represents Glu, Asp or Lys, and when there is a plurality of ABs, each AB may be the same as or different from each other and ABs are bonded to each other via an amide bond; and p represents an integer of 1 to 4; with a proviso that when R 3 or R 4 is -(AB) p , a sum of n and p is an integer of 1 to 5, <EOS>