Prevention and induction of oxidative damage in E. coli cells by cationized proteins

Ron Kohen*, Rima Shalhoub

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The successful prevention of oxidative damage in E. coli B cells by cationized catalase (cCAT), and the induction of oxidative stress by cationized glucose oxidase (cGO) and cationized superoxide dismutase (cSOD) is presented in this study. Exposure of E. coli cells to hydrogen peroxide and hydroxyl radical resulted in a rapid killing of the cells. Measurements of biochemical markers: cellular potassium levels and uptake and accumulation of leucin indicated membrane damage in some of the oxidants employed. Following incubation with native CAT or SOD, the cells were washed and exposed to oxidative stress. The results of this procedure did not protect the cells against the oxidative damage. In contrast, incubation of the cells with pretreated CAT with poly-l-histidine, followed by washing of the cells and the subsequent introduction of oxidative stress inducers, resulted in a pronounced protection of the cells against the oxidative stress. Employment of pretreated SOD, and exposure, after washing the cells, to oxidative stress, resulted in an enhancement of the oxidative damage in some cases. Exposure of the cells to cGO resulted in a marked killing of the cells as compared to the untreated enzyme. The use of E. coli cells as a model system for studying the effect of cationized enzymes on cell surfaces is discussed.

Original languageAmerican English
Pages (from-to)571-580
Number of pages10
JournalFree Radical Biology and Medicine
Issue number5
StatePublished - May 1994

Bibliographical note

Funding Information:
Acknowledgements -- We thank Prof. Isaac Ginsburg (Department of Oral Biology, Hebrew University-Hadassah School of Dental Medicine) for useful discussions and critical comments during the course of this study. This research was supported by a grant obtained from the Wolfson Foundation for Scientific Research.


  • Bacteria
  • Catalase
  • Cationization
  • Free radicals
  • Induction
  • Oxidative stress
  • Prevention
  • Superoxide dismutase


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