Purification and properties of a pepstatin-insensitive carboxyl proteinase from a gram-negative bacterium

Biochim Biophys Acta. 1987 Mar 19;923(3):463-9. doi: 10.1016/0304-4165(87)90055-9.


A carboxyl proteinase was found in the culture filtrate of a Gram-negative bacterium. The optimum for the action of the purified enzyme was approx. pH 3 and its caseinolytic activity was not inhibited by carboxyl proteinase inhibitors, such as pepstatin, Streptomyces pepsin inhibitor and diazoacetyl-DL-norleucine methyl ester. 1,2-epoxy-3-(p-nitrophenoxy)propane modified the enzyme with concomitant loss of its enzyme activity. The enzymatic and physicochemical properties of the enzyme were compared with those of known pepstatin- and diazoacetyl-DL-norleucine methyl ester-insensitive carboxyl proteinases previously reported. To our knowledge, this is the first carboxyl proteinase isolated from bacteria.

MeSH terms

  • Amino Acids / analysis
  • Aspartic Acid Endopeptidases
  • Chemical Phenomena
  • Chemistry, Physical
  • Drug Resistance, Microbial
  • Endopeptidases / isolation & purification*
  • Gram-Negative Bacteria / enzymology*
  • Hydrogen-Ion Concentration
  • Molecular Weight
  • Oligopeptides / pharmacology*
  • Pepstatins / pharmacology*
  • Protease Inhibitors / pharmacology
  • Temperature


  • Amino Acids
  • Oligopeptides
  • Pepstatins
  • Protease Inhibitors
  • Streptomyces pepsin inhibitor
  • Endopeptidases
  • Aspartic Acid Endopeptidases
  • pepstatin