Vipera ammodytes venom phospholipase A2 toxins (Vaa-PLA2)

Vipera ammodytes venom phospholipase A2 (PLA2) toxins are a family of secreted enzymes and their non-enzymatic homologs found in the venom of the nose-horned viper, which is considered the most dangerous venomous snake in Europe (Wikipedia, 2024). The most prominent members are the ammodytoxins (AtxA, AtxB, and AtxC), which act as potent presynaptic beta-neurotoxins by inhibiting the release of neurotransmitters at the neuromuscular junction, leading to flaccid paralysis (NIH, 1994; Toxins, 2022). These toxins also exhibit myotoxic, anticoagulant, and pro-inflammatory activities, contributing to local tissue damage and systemic envenomation symptoms (NIH, 2011; NIH, 2017). In the context of drug development, these toxins are primary targets for neutralization by antivenoms and small-molecule inhibitors like varespladib (MDPI, 2024; Toxins, 2016). Varespladib acts as a competitive inhibitor of the PLA2 enzymatic site, effectively blocking the cascade of events that leads to neurotoxicity and tissue necrosis (Encyclopedia MDPI, 2024). Antivenoms, such as Viperatab, work by binding to and neutralizing the toxins before they can reach their physiological targets (MDPI, 2024).

Other names

AmmodytoxinsAtxNose-horned viper phospholipase A2Beta-neurotoxinsVipera ammodytes sPLA2

Competitive inhibition of phospholipase A2 enzymatic activity and neutralization by specific antibodies.