Interaction between duodenase and Alpha1-proteinase inhibitor

I. P. Gladysheva, N. A. Popykina, T. S. Zamolodchikova, N. I. Larionova

Research output: Contribution to journalArticlepeer-review


The interaction between duodenase, a newly recognized serine proteinase belonging to the small group of Janus-faced proteinases, and alpha1-proteinase inhibitor (alpha1-PI) from human serum was investigated. The stoichiometry of the inhibition was 1.2 mol/mol. The presence of a stable enzyme-inhibitor complex was shown by SDS-PAGE. The mechanism of interaction between duodenase and alpha1-PI was shown to be of the suicide type. The equilibrium and inhibition constants are 13 ± 3 nM and (1.9 ± 0.3)·105 M-1·sec-1, respectively. Based on the association rate constant of the enzyme-inhibitor complex and localization of duodenase and alpha1-PI in identical compartments, alpha1-PI is suggested to be a duodenase inhibitor in vivo.

Original languageEnglish (US)
Pages (from-to)839-845
Number of pages7
Issue number6
StatePublished - 2001
Externally publishedYes


  • Alpha-proteinase inhibitor
  • Duodenase

ASJC Scopus subject areas

  • General Chemistry


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