Electrophoretic analysis of Clostridium botulinum types A and B hemagglutinins

The serologically related hemagglutinins of Clostridium botulinum types A and B were resolved into several bands in polyacrylamide gels in the presence of sodium dodecyl sulfate. Reduction of the samples with mercaptoethanol partly changed the band patterns, but with each hemaglutinin the two fastest moving bands in the reduced and unreduced samples were the same. In type A these two smallest units were of molecular weight 14 500 and 19 500; in type B they were of molecular weight 14 500 and 20 000. The experimentally determined molecular weight of the other resolved units agreed with those calculated on the basis that they were aggregations of the two smallest units in varying but whole multiples.