pyrophosphate and tartaric-acid

Active components of toothpastes which are intended to inhibit plaque mineralization are discussed with their physiological and chemical implications on the formation and calcification of dental plaque. The decisive factors are defined as part of the biocrystallographic reactivity in the oral milieu.

Topics: Dental Calculus; Dental Plaque; Dentifrices; Detergents; Diphosphates; Humans; Tartrates; Toothpastes

Several ecto-enzymatic activities have been described in the plasma membrane of the protozoan Leishmania amazonensis, which is the major etiological agent of diffuse cutaneous leishmaniasis in South America. These enzymes, including ecto-phosphatases, contribute to the survival of the parasite by participating in phosphate metabolism. This work identifies and characterizes the extracellular hydrolysis of inorganic pyrophosphate related to an ecto-pyrophosphatase activity of the promastigote form of L. amazonensis. This ecto-pyrophosphatase activity is insensitive to MnCl2 but is strongly stimulated by MgCl2. This stimulation was not observed during the hydrolysis of p-nitrophenyl phosphate (p-NPP) or β-glycerophosphate, two substrates for different ecto-phosphatases present in the L. amazonensis plasma membrane. Furthermore, extracellular PPi hydrolysis is more efficient at alkaline pHs, while p-NPP hydrolysis occurs mainly at acidic pHs. These results led us to conclude that extracellular PPi is hydrolyzed not by non-specific ecto-phosphatases but rather by a genuine ecto-pyrophosphatase. In the presence of 5mM MgCl2, the ecto-pyrophosphatase activity from L. amazonensis is sensitive to micromolar concentrations of NaF and millimolar concentrations of CaCl2. Moreover, this activity is significantly higher during the first days of L. amazonensis culture, which suggests a possible role for this enzyme in parasite growth.

Topics: Animals; Calcium Chloride; Cell Membrane; Chlorides; Cricetinae; Diphosphates; Dose-Response Relationship, Drug; Humans; Hydrogen-Ion Concentration; Hydrolysis; Leishmania mexicana; Leishmaniasis, Diffuse Cutaneous; Levamisole; Magnesium Chloride; Manganese Compounds; Pyrophosphatases; Sodium Fluoride; Tartrates; Vanadates

The design and synthesis of several beta-1,4-galactosyltransferase inhibitors are reported. Mimics of the pyrophosphate-Mn2+ complex were the focus of the design. Malonic, tartaric, and monosaccharide moieties were used as replacements of the pyrophosphate moiety, and galactose or azasugars with potent galactosidase inhibitory activity were used as the 'donor' component. Compound 6, in which glucose was used as the pyrophosphate-Mn2+ complex mimic and galactose as the 'donor' component, showed the best inhibitory activity towards the transferase with a Ki of 119.6 microM.

Topics: Aminoglycosides; Anti-Bacterial Agents; Antifungal Agents; Antiviral Agents; Binding Sites; Diphosphates; Enzyme Inhibitors; Fucosyltransferases; Malonates; Manganese; Monosaccharides; N-Acetyllactosamine Synthase; Pyrimidine Nucleosides; Substrate Specificity; Tartrates; Tunicamycin