Difference in hydrophobicity between botulinum type B activated and non-activated neurotoxins under low pH conditions

We showed that botulinum type B activated neurotoxin with a di-chain struct ure became hydrophobic more quickly and extensively than did the non-activa ted toxin with a single-chain structure on low pH exposure. The activated t oxin possessed 50-fold higher toxicity than did the non-activated type. The difference in the susceptibility to hydrophobic change may be one clue to answering the question of why the activated toxin possesses a higher toxici ty than does the non-activated type. (C) 2000 Elsevier Science Ltd. All rig hts reserved.