Modification of Amino Acid Residues in Carious Dentin Matrix

• Published in: Journal of dental research Vol. 77; no. 3; pp. 488 - 495
• Main Authors: Kleter, G.A., Damen, J.J.M., Buijs, M.J., Ten Cate, J.M.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.03.1998; SAGE PUBLICATIONS, INC
• Subjects: Agrotechnological Research Institute; Amino Acids - chemistry; Arginine - analogs & derivatives; Arginine - analysis; Chromatography, High Pressure Liquid; Collagen - metabolism; Cross-Linking Reagents - analysis; Dental Caries - metabolism; Dentin - chemistry; Dentin - metabolism; Dentistry; Extracellular Matrix Proteins - metabolism; Glycation End Products, Advanced - analysis; Glycosylation; Humans; Hydrolysis; Hydroxyproline - analysis; Instituut voor Agrotechnologisch Onderzoek; Lysine - analogs & derivatives; Lysine - analysis; Maillard Reaction; Ninhydrin - analysis; Protein Processing, Post-Translational; Spectrometry, Fluorescence; Maillard reaction; dentin; physiological cross-links; caries
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/00220345980770030801

The Maillard reaction between sugar and protein has been postulated as the cause for the browning and arrestment of caries lesions. This reaction has been implicated as the cause for decreased degradability of collagen in vivo. The aim of the present study was to verify the occurrence of the reaction in vivo. Carious and sound dentin samples were taken from extracted human teeth and analyzed for the fluorescence characteristic of the Maillard reaction and oxidation and, by HPLC, for Maillard products. In addition, physiological cross-links were analyzed by HPLC. Oxidation- and Maillard reaction-related fluore-scence increased in collagenase digests from carious dentin. Advanced Maillard products (carboxymethyllysine and pentosidine) increased, whereas furosine, a marker for the initial reaction, was not observed consistently. This implies no direct addition of sugars to protein, but rather the addi-tion of smaller metabolites and glycoxidation products. In addition, the physiological crosslinks hydroxylysinonorleucine and dihydroxylysinonorleucine decreased in carious dentin. Also for hydroxylysylpyridinoline, a decrease was observed, but not consistently. In conclusion, the caries process modifies amino acids in dentin collagen, which can lead to increased resistance against proteolysis and ulti-mately to caries arrestment.