This family consists of toxic peptides that are isolated from the saliva of assassin bugs. The saliva contains a complex mixture of proteins that are used by the bug either to immobilise the prey or to digest it. One of the proteins (Ptu1) has been purified and shown to block reversibly the N-type calcium channels and to be less specific for the L- and P/Q- type calcium channels expressed in BHK cells [1].

1: Solution structure of Ptu1, a toxin from the assassin bug Peirates turpis that blocks the voltage-sensitive calcium channel N-type. Bernard C, Corzo G, Mosbah A, Nakajima T, Darbon H; Biochemistry 2001;40:12795-12800. PMID:11669615