Journal of Dental Research, Vol 74, 1613-1617, Copyright © 1995 by International & American Associations for Dental Research Online Journals
Effect of sucrose monolaurate on acid production, levels of glycolytic intermediates, and enzyme activities of Streptococcus mutans NCTC 10449
Y. Iwami, C. F. Schachtele and T. Yamada
Department of Oral Biochemistry, Tohoku University School of Dentistry, Sendai, Japan.
We studied the mechanism by which the antimicrobial compound sucrose
monolaurate inhibits Streptococcus mutans NCTC 10449 by determining its
effect on the rate of acid production from glucose and sucrose and the
intracellular and extracellular levels of glycolytic intermediates. Sucrose
monolaurate was more effective than either sodium laurate or sodium
fluoride in inhibiting acid production at pH 7.0 from glucose. Inhibition
of acid production was the same when either glucose or sucrose was the
carbon source and in the presence or absence of oxygen. Quantitative
analysis of various glycolytic intermediates revealed that the steps
inhibited by sucrose monolaurate were the reactions catalyzed by
phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase and/or
phosphoglycerate kinase. Since the activities of these enzymes in cell-free
extracts were not decreased by the addition of sucrose monolaurate, the
inhibition of acid production could not be ascribed to direct effects on
the enzymes. A decrease in the rate of acid production with corresponding
elevations in the extracellular levels of glycolytic intermediates
indicates that sucrose monolaurate inhibits S. mutans by altering the
permeability of the cell membrane, which causes a loss of important
metabolites.
