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Studies on the lactoperoxidase system: reaction kinetics and antibacterial activity using two methods for hydrogen peroxide generation
Author(s) -
Dionysius D.A.,
Grieve P.A.,
Vos A.C.
Publication year - 1992
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1992.tb01816.x
Subject(s) - lactoperoxidase , chemistry , hydrogen peroxide , thiocyanate , incubation , escherichia coli , antibacterial activity , nuclear chemistry , enzyme , biochemistry , chromatography , medicinal chemistry , bacteria , peroxidase , biology , genetics , gene
D.A. DIONYSIUS, P.A. GRIEVE AND A.C. VOS. 1992. Components of the lactoperoxidase system were measured during incubation in Isosensitest broth, with enzymatic (glucose oxidase, GO) or chemical (sodium carbonate peroxyhydrate, SCP) means to generate H 2 O 2 . When low levels of thiocyanate (SCN ‐ ) were used in the GO system, H 2 O 2 was detected and lactoperoxidase (LP) was inactivated when SCN ‐ was depleted. With 10‐fold higher SCN ‐ , LP remained active and H 2 O 2 was not detectable. The oxidation product of the LP reaction, most likely hypothiocyanite, was present in low concentrations. When SCP was used for the immediate generation of H 2 O 2 in a system employing low SCN ‐ , half the LP activity was lost within minutes but thereafter it remained stable. Low concentrations of oxidation product were measured and H 2 O 2 was not detected during the course of the experiment. At high SCN ‐ levels, relatively high concentrations of oxidation product were produced immediately, with H 2 O 2 undetectable. The results suggest that the final product of the LP reaction depends on the method of H 2 O 2 generation and the relative proportions of the substrates. Antibacterial activity of the two LPS was tested against an enterotoxigenic strain of Escherichia coli. Both systems showed bactericidal activity within 4 h incubation at 37°C.