Peptide Conjugate
A peptide chemically linked to another molecule — such as a toxin, fluorescent label, PEG chain, or fatty acid — to modify its properties. Peptide-drug conjugates use the peptide as a targeting moiety to deliver payloads specifically to cells expressing the target receptor.
Technical Context
Peptide-drug conjugates (PDCs) use the peptide as a targeting moiety to deliver cytotoxic or therapeutic payloads specifically to cells expressing the target receptor. Components: targeting peptide (binds receptor on target cell surface) + linker (cleavable or non-cleavable, controlling payload release) + payload (cytotoxic drug, radionuclide, fluorescent label, or other therapeutic agent). Lu-177 dotatate is essentially a PDC: targeting peptide (dotatate, a somatostatin analogue) + chelator linker (DOTA) + radioactive payload (Lu-177). Peptide-fluorophore conjugates are used for fluorescence-guided surgery — pegulicianine is an approved peptide-fluorescent dye conjugate for identifying cancer margins during breast surgery. The PDC approach combines the targeting specificity of peptides with the potent biological effects of conjugated payloads.