Inhibition of Escherichia coli respiratory enzymes by the lactoperoxidase-hydrogen peroxide-thiocyanate antimicrobial system

K. Shin, H. Hayasawa, B. Lönnerdal

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

Aims: The lactoperoxidase-hydrogen peroxide-thiocyanate antimicrobial system (LPAS) is known to inhibit bacterial respiration. In the present study, several respiratory enzymes of Escherichia coli were compared in terms of their susceptibility to the LPAS. Methods and Results: Exposure of E. coli to the LPAS, upon which 99.6% of the bacteria were killed, resulted in the following percentage of inactivation of substrate-specific membrane oxidases: succinate (94.2%) > NADH (84.6%) > glycerol-3-phosphate (67.8%) > DL-lactate (64.1%). With the same treatment, substrate-specific membrane dehydrogenases were inactivated as follows: succinate (99.1%) > DL-lactate (53.8%) > glycerol-3-phosphate (45.0%) > NADH (36.8%). Terminal oxidase, however, measured using a ubiquinone analogue (2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone) after reduction, was only 21.4% inactivated by the LPAS. Conclusions: These data suggest that dehydrogenases are the primary targets of the LPAS in the respiratory chain of E. coli. Significance and Impact of the Study: This study has determined for the first time the primary targets of LPAS in the bacterial respiratory chain.

Original languageEnglish (US)
Pages (from-to)489-493
Number of pages5
JournalJournal of Applied Microbiology
Volume90
Issue number4
DOIs
StatePublished - 2001

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Applied Microbiology and Biotechnology
  • Biotechnology
  • Microbiology

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