This family contains both neurotoxins and plant defensins. The mustard trypsin inhibitor, MTI-2, is a plant defensin. It is a potent inhibitor of trypsin with no activity towards chymotrypsin. MTI-2 is toxic for Lepidopteran insects, but has low activity against aphids. Brazzein is a plant defensin-like protein. It is pH-stable, heat-stable and intensely sweet protein. The scorpion toxin (a neurotoxin) binds to sodium channels and inhibits the activation mechanisms of the channels, thereby blocking neuronal transmission.