ANTIINSECT TOXIN-5 (AAIT5) FROM ANDROCTONUS-AUSTRALIS

An insect-selective scorpion toxin (AaIT5) was purified from the venom of the North African scorpion Androctonus australis, and its amino ac id sequence was determined by a combination of automated Edman degrada tion, electrospray-ionization mass spectrometry, and sequence alignmen t. This insect toxin is very potent against the tobacco budworm, Helio this virescens (100% lethal dose <1.8 mu g/100 mg body mass) and shows a distinct insect specificity and various symptoms. It is not toxic t o mice after subcutaneous injection. The molecular mass of this toxin is 6882 Da and the amino acid sequence is similar to those of Androcto nus australis anti-insect toxin 4 (AaIT4), Leiurus quinquestriatus dep ressant anti-insect toxins (LqhIT2, LqqIT2), and Buthotus judaicus dep ressant anti-insect toxin (BjIT2).