Paradoxin (PDX) is a presynaptic neurotoxic phospholipase found in the venom of the inland taipan (Oxyuranus microlepidotus), an extremely venomous species of snake native to Australia.
It is similar in structure to another neurotoxin named taipoxin. However they differ in how they are neurotoxic. It is a heterotrimer and composed of three subunits.
Relatively little is known about paradoxin including its neuromuscular activity. It is known that paradoxin blocks nerve impulses in the synapses by disrupting and blocking neuromuscular transmission.