CE–LIF determination of salivary cadaverine and lysine concentration ratio as an indicator of lysine decarboxylase enzyme activity

Abstract

Salivary bacteria produce the enzyme lysine decarboxylase which converts lysine to cadaverine. In the absence of appropriate oral hygiene, overgrowth of these bacteria depletes lysine. This may contribute to gingival inflammation, while cadaverine contributes to oral malodor. A selective and sensitive capillary electrophoresis method with laser-induced fluorescence detection has been developed for the determination of cadaverine and lysine in saliva, as an indicator of lysine decarboxylase enzyme activity. The diamino compounds were separated in acidic background electrolyte in their mono-labeled form after derivatization with 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole (NBD-F). Linearity and reproducibility of the method in the range 1-50 μmol L(-1) have been demonstrated using saliva samples. The method was applied for the measurement of cadaverine and lysine in the saliva of healthy volunteers with or without proper oral hygiene. In the absence of oral hygiene, the mol fraction of cadaverine to cadaverine plus lysine in saliva increased significantly (0.65 ± 0.13 vs. 0.39 ± 0.18, P < 0.001), indicating the presence of higher amount of bacterial lysine decarboxylase, that may contribute to periodontal diseases.

Bacterial Lysine Decarboxylase Influences Human Dental Biofilm Lysine Content, Biofilm Accumulation, and Subclinical Gingival Inflammation

“…Losses were adjusted by internal standard recovery. Assay accuracy and precision were ~6% as reported in detail previously 38 . In addition, because lysine is the sole source of cadaverine which is stable in the oral cavity 39 , totaling the cadaverine plus lysine content of dental biofilm indicates lysine converted to cadaverine plus lysine remaining (‘total’ lysine content).…”

“…Cadaverine and lysine were determined as described previously by our group 38 . Biofilm samples were placed in pre-weighed micro-centrifuge tubes and weighed using an analytical balance.…”

Biofilm Lysine Decarboxylase, a New Therapeutic Target for Periodontal Inflammation

“…It was reported previously in detail how lysine, cadaverine, and TA were measured in biofilm samples by capillary electrophoresis coupled to laser-induced fluorescence. 5,30 The cadaverine fraction, described in the legend to Table 1, is a measure of in vivo LDC activity. 5,31 Statistical Analyses ¶ ¶ Measurements after OHR with TA were compared with those reported previously without TA and at baseline for the same individuals (Table 1) using Friedman test, followed by Nemenyi multiple comparisons and the Bonferroni correction.…”

Comparison of quantitative performance of three fluorescence labels in CE/LIF analysis of aspartate and glutamate in brain microdialysate

“…The optimization of derivatization conditions was described in our previous paper [37]. Hundred-millimolar borate buffer of pH 8.5 was chosen as BGE.…”