Patent ID: 8512675

Claim:
A compound comprising: a histidine derivative derivatized at N ε with a constituent comprising a biomolecule, wherein the histidine derivative has a formula (X) or (XV): wherein BM is a biomolecule, M is radioactive metal, n is an integer from 1 to 5, and X′ is a coupling block selected from the group consisting of —N(H)—C(O)—, —C(O)—N(H)—, —O—P(O − )(O)—O—, —S-halide-, —S-azide-, —S-pseudohalide-, —S-phosphate-, —S-thiol-, —S-silyl-, —O-halide-, —O-azide-, —O-pseudohalide-, —O-phosphate-, —O-thiol-, —O-silyl-, —N(H)-halide-, —N(H)-azide-, —N(H)-pseudohalide-, —N(H)-phosphate-, —N(H)-thiol- and —N(H)-silyl-.