[des-Arg1]-Proctolin: A novel NEP-like enzyme inhibitor identified in Tityus serrulatus venom

Publication date: Available online 6 June 2015 Source:Peptides Author(s): Bruno Duzzi , Daniela Cajado-Carvalho , Alexandre Kazuo Kuniyoshi , Roberto Tadashi Kodama , Fabio Cesar Gozzo , Mariana Fioramonte , Denise Vilarinho Tambourgi , Fernanda Vieira Portaro , Vanessa Rioli The scorpion Tityus serrulatus venom comprises a complex mixture of molecules that paralyzes and kills preys, especially insects. However, venom components also interact with molecules in humans, causing clinic envenomation. This cross-interaction may result from homologous molecular targets in mammalians and insects, such as (NEP)-like enzymes. In face of these similarities, we searched for peptides in Tityus serrulatus venom using human NEP as a screening tool. We found a NEP-inhibiting peptide with the primary sequence YLPT, which is very similar to that of the insect neuropeptide proctolin (RYLPT). Thus, we named the new peptide [des-Arg1]-proctolin. Comparative NEP activity assays using natural substrates demonstrated that [des-Arg1]-proctolin has high specificity for NEP and better inhibitory activity than proctolin. To test the initial hypothesis that molecular homologies allow Tityus serrulatus venom to act on both mammal and insect targets, we investigated the presence of a NEP-like in cockroaches, the main scorpion prey, that could be likewise inhibited by [des-Arg1]-proctolin. Indeed, we detected a possible NEP-like in a homogenate of cockroach heads whose activity was blocked by ...

Source: Peptides - June 27, 2015 Category: Biochemistry Source Type: research