Functional characterization of Narc 1, a novel proteinase related to proteinase K

Arch Biochem Biophys. 2003 Dec 1;420(1):55-67. doi: 10.1016/


The NARC 1 gene encodes a novel proteinase K family proteinase. The domain structure of rat Narc 1 resembles that of the subtilisin-like proprotein convertases (SPCs), except that rNarc 1 lacks the canonical P-domain of SPCs, retaining only the RGD motif as part of what might be a cryptically functioning P-domain. Narc 1 undergoes autocatalytic intramolecular processing at the site LVFAQ/, resulting in the cleavage of its prosegment and the generation of an active proteinase with a broad alkaline pH optimum and no apparent calcium requirement for activity. Both primary and secondary structural determinants influence Narc 1 substrate recognition. Our functional characterization of Narc 1 reinforces the inference drawn from the analysis of its predicted structure that this enzyme is most closely related to representatives of the proteinase K family, but that it is also sufficiently different to warrant its possible classification in a separate sub-family.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Calcium / chemistry
  • Endopeptidase K / chemistry*
  • Endopeptidase K / metabolism*
  • Enzyme Activation
  • Enzyme Stability
  • Gene Expression Regulation, Enzymologic / physiology
  • Hydrogen-Ion Concentration
  • Models, Chemical*
  • Molecular Sequence Data
  • Oligopeptides / chemistry
  • Proprotein Convertase 9
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Rats
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Sequence Alignment*
  • Sequence Analysis, Protein*
  • Sequence Homology
  • Serine Endopeptidases / chemistry*
  • Serine Endopeptidases / metabolism*
  • Structure-Activity Relationship
  • Temperature


  • Oligopeptides
  • Recombinant Proteins
  • arginyl-glycyl-aspartic acid
  • PCSK9 protein, rat
  • Proprotein Convertase 9
  • Serine Endopeptidases
  • Endopeptidase K
  • Calcium