Specificity of endoproteinase Asp-N (Pseudomonas fragi): cleavage at glutamyl residues in two proteins.
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.
Ingrosso
D
D
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024-1569.
Fowler
A V
AV
Bleibaum
J
J
Clarke
S
S
D000595:Amino Acid Sequence; D001224:Aspartic Acid; D010450:Endopeptidases / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology; D005971:Glutamates; D013058:Mass Spectrometry; D008666:Metalloendopeptidases / Q000378:metabolism*; D008780:Methyltransferases / Q000097:blood*; D008969:Molecular Sequence Data; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase; D011496:Protein Methyltransferases / Q000235:genetics / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*; D013379:Substrate Specificity
D005971:Glutamates; D001224:Aspartic Acid; D008780:Methyltransferases; D011496:Protein Methyltransferases; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase; D010450:Endopeptidases; D008666:Metalloendopeptidases; C058921:endoproteinase Asp-N