Polypeptide derivatives

A physiologically peptide selected from the group consisting of growth factors, peptide hormones, interferons and cytokines and analogues or derivatives thereof, and bearing a chelating group linked either directly or indirectly by means of a divalent bridging group to an amino group of said peptide, the chelating group being derived from N′-p-isothiocyanatobenzyl-diethylene triamine-N,N,N″,N″-tetraacetic acid, N′-p-isothiocyanatophenethyl-diethylene triamine-N,N,N″,N″-tetraacetic acid, N-{2-[bis(carboxymethyl)amino]ethyl}-N′-{2-[bis(carboxymethyl)amino]-2-(p-isothiocyanatobenzyl)-ethyl}-glycine, DOTA, C-functionalised tetraazacyclododecane-tetraacetic acids, C-functionalised tetraazacyclotetradecane-tetraacetic acids, C-functionalised triazacyclododecane triacetic acids, C-functionalised triazacyclononane triacetic acids and a compound of formula V

• 29
• wherein
• each of R24, R25, R26, R27, R28 and R29 independently is hydrogen or C1-4alkyl,
• m′ is 2 or 3, and
• X2 is p-isothiocyanato-benzyl or -phenethyl,
• the chelating group being capable of complexing a detectable element and said amino group having no significant binding affinity to target receptors.

A compound of formula XI

• A-Z-R-Z2-X7 (XI)
• wherein
• A is a chelating group,
• Z is a divalent group derived from a functional moiety capable of covalently reacting with a chelating agent,
• R is C1-11alkylene, hydroxy substituted C2-11alkylene, C2-11alkenylene,
• 33
• cyclohexylene, substituted cyclohexylene, or a radical of formula (α2)
• 34
• wherein each of n and m independently is 0, 1, 2 or 3,
• the ring A is substituted or unsubstituted, and
• R5 is a residue as attached in Cα of a natural or synthetic α-amino acid, and
• Z2 is COOH or a functional group of a carboxy function,
• or a compound of formula XII
• A-Z′1l-CO—X7 (XII)
• wherein
• A is as defined above,
• Z′1 is either a direct bond or -Z-R wherein Z and R are as defined above, and
• X7 is —NH—NH2 in protected or unprotected form or —N3.