Enzymes in Carious Human Dentine a Histochemical Akd Biochemical Study

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Abstract
Human carious dentine was excavated in situ or obtained from extracted teeth and sound dentine samples were prepared from extracted teeth. the dentine samples were cut in a cry-ostat for histochemical studies or crushed in a mortar for biochemical analyzes. Hydrolysis of ntimerous naphtol deriwtes was histochemically detected in dental plaque and in the tubules of carious dentine, indicating the occurrence of the following hydrolases in the structures: arylaniinopeptidases (EC 3.4.1.1.–3.4.1.3.). nonspecific esterases (EC 3.1.1.), alkaline phos-phatase (EC 3.1.3.1.), acid phosphatase (3.1.3.2.), ATPase (3.6.1.3.), phosphoamidase (EC 3.9.1.1.), α-glucosidase (EC 3.2.1.20.), β-glucosidase (EC 3.2.1.21.), βgalactosidase (EC 3.2.1.23.), β-glucuronidase (EC 3.2.1.31.), and arylsulphatase (EC 3.1.6.1.). Aryliminopeptidase (EC 3.4.1.4.) was observed only in dental plaque. Chitobiase activity (EC 3.2.1.29.) was not denionstrahle in any structures. None of these enzyme activities was histochemically demonstrable in sound human dentine, whereas acid and alkaline phosphatase and α-glucosidase actibities were additionally observed in the predentine. Histochemical studies further revealed the occurrence of the following oxidoreductases in dental plaque and in the tubules of carious dentine: lactate dehydrogenase (EC 1.1.1.27.), glucose 6-phosphate dehydrogenase (EC 1.1.1.49.), succinate dehydrogenase (EC 1.3.99.1.), glutamate dehydrogenase (EC 1.4.1.2.), glutathione reductase (EC 1.6.4.2.), and lipoamide reductase (EC 1.6.4.3.). Cystine reductase (EC 1.6.4.1.), alanine (EC 2.6.1.2.) and aspartate aminotransferases (EC 2.6.1.1.) were biochemically demonstrated in carious human dentine. These observations were thought to map a part of the metabolism catalyzed by enzymes in dentine during the propagation of caries.