Altitoxin

Altitoxin is a neurotoxin found in the South African scorpion Parabuthus transvaalicus. Injection of altitoxin in mice leads to akinesia, depression and death.^[1]

Sources

South African spitting scorpion (Parabuthus transvaalicus)

Altitoxin is secreted by the venom gland of the South African spitting (or fattail) scorpion Parabuthus transvaalicus.^[1]

Chemistry

Altitoxin, with the amino acid sequence ADVPGNYPLDKDGNTYTCLELGENKDCQKVCKLHGVQYGYCYAFFCWCKELDDKDVSV, is 58 amino acid residues long and has a molecular mass of 6598 Da; it has 3 disulfide bridges (Cys18-Cys41, Cys27-Cys46, and Cys31-Cys48).^[1] It has large homology to other toxins from the venom of Parabuthus transvaalicus, including bestoxin, birtoxin, ikitoxin and dortoxin.

Target

Altitoxin has sequence homology to scorpion β-toxins, suggesting it might target sodium channels. However, its depressing action following injection into mice ^[1] is not in agreement with the effect of β-toxins on sodium channels. Related scorpion toxins, which include birtoxin and bestoxin, exhibit highly divergent biological activity,^[1] indicating that the mode of action of these toxins is highly diverse.

Toxicity

An injection of 100 ng altitoxin in 20 g mouse (ED99) causes a state of akinesia and depression. Lethality is reached at injecting 200 ng.^[1]

References

^ ^a ^b ^c ^d ^e ^f Inceoglu, B.; Lango, J.; Pessah, I. N.; Hammock, B. D. (2005). "Three structurally related, highly potent, peptides from the venom of Parabuthus transvaalicus possess divergent biological activity". Toxicon. 45 (6): 727–33. doi:10.1016/j.toxicon.2005.01.020. PMID 15804521.

[toxicon-1] ^ ^a ^b ^c ^d ^e ^f Inceoglu, B.; Lango, J.; Pessah, I. N.; Hammock, B. D. (2005). "Three structurally related, highly potent, peptides from the venom of Parabuthus transvaalicus possess divergent biological activity". Toxicon. 45 (6): 727–33. doi:10.1016/j.toxicon.2005.01.020. PMID 15804521.

[1]