INTERACTION OF BOTULINUM TYPE-A, TYPE-B, AND TYPE-E DERIVATIVE TOXINS WITH SYNAPTOSOMES OF RAT-BRAIN

Clostridium botulinum125I-labelled derivative toxin immediately bound to rat synaptosomes. Of the two fragments of type B derivative toxin, the large-molecular-weight fragment (fragment I) inhibited the binding of labelled type B derivative toxin to synaptosomes in the same manner as unlabelled type B toxin did. The inhibition by the small-molecular-weight fragment (fragment II) was less than that by fragment I. These findings suggest that type B toxin binds to synaptosomes mainly with some part of fragment I. The binding of labelled type A and E derivative toxins was inhibited by either of the unlabelled type A or E derivative toxins, but not by type B derivative toxin. It is concluded that synaptosomes of rat brain possess relatively specific binding sites for botulinum toxin types. © 1979 Springer-Verlag.