Specificity of endoproteinase Asp-N (Pseudomonas fragi): cleavage at glutamyl residues in two proteins

Biochem Biophys Res Commun. 1989 Aug 15;162(3):1528-34. doi: 10.1016/0006-291x(89)90848-6.


Endoproteinase Asp-N, a metalloprotease from a mutant strain of Pseudomonas fragi, has been reported to specifically cleave on the N-terminal side of aspartyl and cysteic acid residues. We utilized this enzyme to generate fragments for determining the amino acid sequence of the D-aspartyl/L-isoaspartyl methyltransferase isozyme I from human erythrocytes. Surprisingly, we identified cleavage sites for this enzyme at the N-terminal side of several glutamyl residues in addition to the expected cleavage sites at aspartyl residues. The ability of this enzyme to cleave polypeptides at both glutamyl and aspartyl residues was confirmed by mapping additional sites on erythrocyte carbonic anhydrase I. These results indicate that a more appropriate name for this enzyme may be Endoproteinase Asp/Glu-N.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Aspartic Acid
  • Endopeptidases* / metabolism*
  • Erythrocytes / enzymology
  • Glutamates
  • Mass Spectrometry
  • Metalloendopeptidases / metabolism*
  • Methyltransferases / blood*
  • Molecular Sequence Data
  • Protein D-Aspartate-L-Isoaspartate Methyltransferase
  • Protein Methyltransferases / genetics
  • Protein Methyltransferases / metabolism*
  • Pseudomonas / enzymology*
  • Substrate Specificity


  • Glutamates
  • Aspartic Acid
  • Methyltransferases
  • Protein Methyltransferases
  • Protein D-Aspartate-L-Isoaspartate Methyltransferase
  • Endopeptidases
  • Metalloendopeptidases
  • endoproteinase Asp-N