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Inhibition of Escherichia coli respiratory enzymes by the lactoperoxidase‐hydrogen peroxide‐thiocyanate antimicrobial system
Author(s) -
Shin K.,
Hayasawa H.,
Lönnerdal B.
Publication year - 2001
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2001.01268.x
Subject(s) - lactoperoxidase , escherichia coli , biochemistry , respiratory chain , chemistry , antimicrobial , hydrogen peroxide , succinate dehydrogenase , thiocyanate , enzyme , microbiology and biotechnology , peroxidase , biology , gene
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.