Venom preparation from Conus anemone contains a component that binds radiolabeled neuropeptide Y ([3H]neuropeptide Y) with high affinity (KD = 2.9 nM ± 0.2 nM, Bmax = 15.2 ± 0.5 pmol/mg protein). Binding of [3H]neuropeptide Y to the venom component is displaced with nanomolar affinity of unlabeled human and porcine neuropeptide Y, porcine [Leu31-Pro34]neuropeptide Y, peptide YY, avian and bovine pancreatic polypeptide, and the (18–36) and (25–36) C-terminal fragments from neuropeptide Y. No displacement is found with the (1–24) N-terminal neuropeptide Y fragment, human secretin, porcine dynorphin A and Boc-DAKLI (Bolton Hunter coupled dynorphin A analog kappa ligand) nor with the non-peptide neuropeptide Y receptor antagonist BIBP3266. Gel filtration chromatography and denaturing (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) show that the [3H]neuropeptide Y-binding component is very likely a single-chain polypeptide with a molecular mass of 18.5 kDa. |
