Enzyme destruction by a protease contaminant in bacitracin

Biochem Biophys Res Commun. 2000 Jul 14;273(3):829-32. doi: 10.1006/bbrc.2000.3029.


Bacitracin, as purchased from biochemical supply companies, is a mixture of more than 30 different substances. The major antibiotic isoforms A and B account for about 60% of the mixture. A newly identified impurity in some, but not all, of the bacitracin lots is a powerful subtilisin-type protease capable of cleaving many proteins including protein disulfide isomerase (PDI), myosin, and a variety of artificial substrates Thus, it is important for investigators who use bacitracin as a protease or other enzyme inhibitor to determine if the bacitracin they are using is contaminated with a protease enzyme. If it is present, they may have to reinterpret their results and retest with an enzyme-free bacitracin reagent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacitracin / chemistry
  • Bacitracin / pharmacology*
  • Drug Contamination*
  • Enzyme Inhibitors / pharmacology*
  • Enzymes / metabolism*
  • Humans
  • Serine Endopeptidases / blood
  • Subtilisins / analysis
  • Subtilisins / pharmacology*


  • Enzyme Inhibitors
  • Enzymes
  • Bacitracin
  • Serine Endopeptidases
  • Subtilisins