The potent mitogen Pasteurella multocida toxin is highly resistant to proteolysis but becomes susceptible at lysosomal pH

FEBS Lett. 1995 Feb 20;360(1):62-6. doi: 10.1016/0014-5793(95)00077-m.


The susceptibility of the potent mitogen Pasteurella multocida toxin (PMT) to various proteases was investigated. PMT at a toxin to protease molar ratio of 1:1 was resistant to 8 of the 11 proteases tested after one hour. With longer incubation, PMT remained resistant to 7 proteases, and this correlated with a retention of biological activity, indicating that PMT might not require proteolytic cleavage at least until it bound to a cell receptor. Previous evidence had suggested that PMT is processed in the cell via an endosome or lysosome. We have shown that PMT became susceptible to proteolysis when the pH was lowered to 5 or below. This supports the previous suggestion that PMT is processed via a low pH compartment in the cell.

MeSH terms

  • 3T3 Cells
  • Animals
  • Bacterial Proteins*
  • Bacterial Toxins / metabolism*
  • Detergents
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Lysosomes / metabolism*
  • Mice
  • Mitogens / metabolism*
  • Pasteurella multocida / metabolism*
  • Protein Denaturation
  • Urea / chemistry


  • Bacterial Proteins
  • Bacterial Toxins
  • Detergents
  • Mitogens
  • Pasteurella multocida toxin
  • Urea