POLYPEPTIDE HAVING RADIOACTIVE GALLIUM BINDING SITE, AND RADIOACTIVE GALLIUM COMPLEX THEREOF

摘要

The present invention is a polypeptide, which is an exendin-4 peptide derivative, or a salt thereof. Said polypeptide comprises an amino acid sequence represented by Y-QMEEEAVRLFIEWLKNGGPSSGAPPPS-NH2 (I). In formula (I), Y- represents an N-terminalα-amino group being attached to a C-terminal carboxyl group of an amino acid sequence represented by any one of B-DLSK (II), H2N-DLSX (III), B-HGEGTFTSDLSK (IV) or H2N-HGEGTFTSDLSX (V). In formulas (II) and (IV), B- represents an N-terminalα-amino group modified by a modifying group having a radioactive gallium binding site. In formulas (III) and (V), X represents a lysine residue modified by a modifying group wherein a side chain amino group has a radioactive gallium binding site. The N-terminalα-amino group of the aforementioned B- and the side chain amino group of the lysine residue of the aforementioned X are each a polypeptide or a salt thereof, modified by a modifying group having a radioactive gallium binding site represented by the prescribed general formula.