Amino-acid Sequences of the Active-Site Sulfhydryl Peptide and Other Thiol Peptides From the Cysteine Proteinase Alpha-Clostripain

Eur J Biochem. 1983 Feb 15;130(3):473-9. doi: 10.1111/j.1432-1033.1983.tb07174.x.


One free -SH group in the heavy chain of alpha-clostripain reacts rapidly with N-tosyllysine chloromethyl ketone which inactivates the enzyme. Iodoacetic acid also reacts with the thiol group required for enzyme activity but more slowly. A tryptic peptide containing the reactive sulfhydryl group labelled with iodo[1-14C]acetic acid was isolated and determined to be Gln-Ser-Val-Asp-Leu-Leu-Ala-Phe-Asp-Ala-Cys-Met. All other cysteine peptides were isolated from the trypsin hydrolysate of the [14C]carboxymethylated enzyme. Moreover N-terminal and C-terminal sequences of both chains of alpha-clostripain were determined. The sequences representing 20% of the primary structure of alpha-clostripain are not homologous with either other cysteine proteinases or with any other protein structure known to date.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Chemical Phenomena
  • Chemistry
  • Cysteine Endopeptidases*
  • Endopeptidases*
  • Peptide Fragments / isolation & purification*
  • Sulfhydryl Compounds / isolation & purification*


  • Peptide Fragments
  • Sulfhydryl Compounds
  • Endopeptidases
  • Cysteine Endopeptidases
  • clostripain