CLEAVAGE OF THE SYNAPTOBREVIN VESICLE-ASSOCIATED MEMBRANE-PROTEIN (VAMP) OF THE MOUSE-BRAIN BY THE RECOMBINANT LIGHT-CHAIN OF CLOSTRIDIUM-BOTULINUM TYPE-B TOXIN

The light chain of Clostridium botulinum type B toxin was expressed in Escherichia coli using the expression Vector pET-3a containing phage T-7 promoter. The expressed protein was then purified by DEAE-cellulos e and phosphocellulose chromatography and the proteolytic activity of the purified light chain was studied. The purified recombinant light c hain cleaved synaptobrevin when mixed with the mouse brain microsome a nd the proteolytic activity of the light chain was inhibited if a meta l chelating agent such as EDTA or 2,2'-dipyridyl was added. The recomb inant light chain cleaved synaptobrevin more effectively than the nati ve type B toxin. When the native toxin was trypsinized and was reduced with DTT, its proteolytic activity was similar to that of the recombi nant light chain.