Venom tetrapeptide that inhibits activities of the human peptidase neprilysin (NEP/MME) (Ki=0.94 uM), the two mammalian endopeptidases EP24.16 and EP24.15 (Ki=36 uM and 74 uM, respectively), and a probable cockroach neprilysin-like protein. It shows 3-fold better inhibitory activity than proctolin. It may play a role in human envenomation as well as in the paralysis and death of scorpion preys. It does not inhibit ACE activity. Expressed by the venom gland. Is a stable peptide that is not originated from proctolin hydrolysis.