Positive co-operative interaction between the subunits of CeqI restriction endonuclease

Z. Jobbagy, Z. Izsvak, E. Duda

Research output: Contribution to journalArticle

4 Citations (Scopus)


CeqI restriction endonuclease, an isoschizomer of EcoRV, forms complexes of 12-20 subunits under physiological conditions, in the absence of DNA. These molecules partially dissociate in the presence of DNA sequences recognized by CegI or in the presence of non-ionic detergents. In solutions containing high concentrations of salts (e.g. I M-NaCI), the enzyme dissociates into subunits, concomitantly losing its activity. According to our experiments, it is the tetrameric form of the enzyme that binds the DNA and represents the catalytically active molecule. Analysis of the enzyme kinetics revealed a positive co-operative interaction between the subunits of the enzyme. Computer-assisted analysis of these data yielded a Hill coefficient of approx. 1.35, suggesting two binding sites per tetrameric enzyme molecule, two subunits per palindromic recognition site.

Original languageEnglish
Pages (from-to)85-88
Number of pages4
JournalBiochemical Journal
Issue number1
Publication statusPublished - Jan 1 1992

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Positive co-operative interaction between the subunits of CeqI restriction endonuclease'. Together they form a unique fingerprint.

  • Cite this