Interaction of duodenase with serpins from human blood serum

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

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1 Scopus citations


The interaction of duodenase, a new serine protease from a small group of Janus-faced proteases, with serpins, α1-protease inhibitor (α1-PI) and antichymotrypsin (ACT) from human blood serum, was studied. The stoichiometry of the inhibition process was found to be 1.2 and 1.3 mol/mol for α1-PI and ACT, respectively. The presence of a stable enzyme-inhibitory complex duodenase-α1-PI was confirmed by SDS-PAGE. The formation of the duodenase-ACT complex was not demonstrated; instead, the band of the cleaved inhibitor indicated the ACT hydrolysis. The suicide mechanism of the duodenase interaction with the human blood serpins was proved. The association rate constants (ka × 105, M-1 s-1) were 2.4 ± 0.3 × 105 for α1-PI and 3.0 ± 0.4 × 105 for ACT. These results indicate the possibility of the regulation of duodenase activity by endogenous serpins.

Original languageEnglish (US)
Pages (from-to)550-555
Number of pages6
JournalRussian Journal of Bioorganic Chemistry
Issue number6
StatePublished - Nov 2003
Externally publishedYes


  • Antichymotrypsin
  • Duodenase
  • Serpins
  • α-inhibitor of proteases

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry


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