Interacts with high affinity with oxytocin receptor (OXTR) (Ki=108 nM) and vasopressin V1a receptor (V1aR/AVPR1A) (Ki=319 nM). Acts as a partial agonist on OXTR (Kact=37 nM, 22% of oxytocin maximum activity at 10 uM), and as a full antagonist on V1aR (Kinact=329 nM). Expressed by the venom duct. The cysteine framework is C-C. Monoisotopic mass. Does not show binding with vasopressin V1b and V2 receptors (up to 10 uM). Shows a weak agonist activity on V1bR/AVPR1B (9% at 10 uM). Belongs to the vasopressin/oxytocin family. L7P mutant