title: Method for determination of invertase activity in homogenates of human dental plaque.
abstract: Supragingival human dental plaque was collected from patients with evidence of caries. The plaque was frozen and stored at -20 degrees C. Pooled plaque was homogenized in acetate buffer pH 5.0 in an ice-water bath. By incubating the homogenate at pH 5.0 with [U-14C]-sucrose the formation of glucose and fructose was followed. Incubation in acetate buffer at pH 5.0 eliminated the glycosyltransferase activities and the glycolytic pathway. Normal Michaelis-Menten kinetics were observed until about 40 mM sucrose. At higher concentration of sucrose, excess substrate inhibition occurred. Storage of the homogenate at -20 degrees C resulted in decrease of the invertase activity with time.
mesh_terms: D002854:Chromatography, Paper; D003731:Dental Caries / Q000378:metabolism; D003773:Dental Plaque / Q000201:enzymology*; D006026:Glycoside Hydrolases / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013395:Sucrose / Q000378:metabolism; D043324:beta-Fructofuranosidase
chemical_list: D013395:Sucrose; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase