Abstract
A heat-labile dermonecrotic toxin was purified from sonic bacterial extracts of serotype D strain of Pasteurella multocida of pig origin. The purified toxin was a protein with a molecular weight ca. 160, 000. Treatment of the mildly trypsinized toxin with dithiothreitol and sodium dodecyl sulfate (SDS) produced three polypeptide chains of molecular weight of ca. 23, 000 (fragment a), ca. 67, 000 (fragment b), and ca. 74, 000 (fragment c). Without pretreatment with trypsin, dithiothreitol and SDS failed to dissociate the polypeptides. None of the dissociated fragments showed detectable toxicity.
