The major excreted protein (MEP) of transformed mouse cells and cathepsin L have similar protease specificity

Susannah Gal, Michael M. Gottesman

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The major excreted protein of transformed mouse cells is an acid activable cysteine protease (1). In this paper, oxidized insulin B chain is shown to be a substrate for this protease. By isolation and analysis of the insulin B peptides generated by the protease, the bond specificity of this protease was determined. The bonds preferentially cleaved are glu13-a1a14, leu17-val18, and tyr26-thr27. No obvious preference for a specific amino acid was found in these studies. The bond specificity of this cysteine protease for oxidized insulin B chain has been compared with that of other proteases, and it is the same as that reported for cathepsin L, suggesting that the major excreted protein and cathepsin L may be the same protein.

Original languageEnglish (US)
Pages (from-to)156-162
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - Aug 29 1986


All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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