Effect of Bacitracin on the Degradation of a Vasopressin Receptor Ligand with High Affinity for the V1 and V2 Vasopressin Isoreceptors

N-[I]L-Tyr-[Lys]-vasopressin was processed in a temperature-dependent manner by crude cell membranes from LLC-PKi cells. Only one degradation product was seen using RP-HPLC. The degradation product co-eluted with monoiodotyrosine. The stereoisomer, N-[I]D-Tyr-[Lys]-vasopressin, underwent the same degradation process. Bacitracin prevented degradation at doses as low as 40 mg/1 without alterating the binding affinity.