Effect of lactoperoxidase system on glucosyltransferase D of Streptococcus mutans.
OBJECTIVE
To investigate the effects of the peroxidase system (LP, H2O2, SCN) and its components on the activity of glucosyltransferase D (GtfD) originating from Streptococcus mutans (S. mutans).


METHODS
GtfD was incubated in buffered-KCl assay mixture that contained 20 microM dextran and 100 mM sucrose including 14C-glucose. The activity of GtfD was measured with a scintillation counter. The effects of lactoperoxidase system and its components on GtfD activity were examined by incubating different components separately and together with GtfD.


RESULTS
The lactoperoxidase system-generated hypothiocyanite (OSCN) had no effect on the activity of streptococcal GtfD, while the lactoperoxidase enzyme inhibited GtfD. The ratio between the 2 enzymes, LP and GtfD, was important for the inhibition. However, if LP was combined with its substrates, SCN and/or a high concentration of H2O2, it enhanced the activity of GtfD.


CONCLUSIONS
Peroxidase-generated antimicrobial agent HOSCN/OSCN is not inhibitory against GtfD, whereas low concentrations of the LP-enzyme inhibit GtfD.
Yu
X
X
Department of Stomatology, 1st Clinical College, Harbin Medical University, No. 23, Youzheng Street, Nangang District, Harbin-150001, Heilongjiang Province, P. R. China.
Loimaranta
V
V
Lenander-Lumikari
M
M
Wunder
D
D
Bowen
W H
WH
Tenuvuo
J
J
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D002250:Carbon Radioisotopes; D003911:Dextrans / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000187:drug effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000494:pharmacology; D007784:Lactoperoxidase / Q000008:administration & dosage / Q000494:pharmacology*; D019275:Radiopharmaceuticals; D013295:Streptococcus mutans / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D013861:Thiocyanates / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002250:Carbon Radioisotopes; D003911:Dextrans; D004791:Enzyme Inhibitors; D019275:Radiopharmaceuticals; D013861:Thiocyanates; D013395:Sucrose; C014607:hypothiocyanite ion; D006861:Hydrogen Peroxide; D007784:Lactoperoxidase; D005964:Glucosyltransferases; C113848:glucosyltransferase D; D005947:Glucose; C031760:thiocyanate