Formation microequilibria of proton, calcium and magnesium complexes of the γ-carboxyglutamate ion and related compounds

Determination of microscopic acid?base parameters from NMR?pH titrations

“…The distribution curve of HL is decomposed into those of protonation isomers N and S. For instance, the mole fraction of microspecies S is given at an arbitrary pH by the following equation: [104]. Designation of microconstants in Fig.…”

Determination of the Thermodynamic Stability Constant of the Magnesium Complex of Malonic Acid by Using an Ion-Exchange/Inductively Coupled Plasma Atomic Emission Spectroscopy Method

“…Values of 2.90, 2.93, and 2.94 were obtained for data collected at ionic strengths of 0.1, 0.15, and 0.2. The log , values reported in the literature, almost all of which were calculated from measurements at lower ionic strengths, are 2.86 (Burger et al, 1988;Jones and Stock, 1962; Klaning and Osterby, 1976), 2.84 (Evans and Monk, 1952), and 2.80 (Money and Davies, 1932). For the experimental reasons described earlier it was not feasible for us to measure equilibrium constant values at ionic strengths below 0.1.…”

Preparation, characterization and biological relevance of calcium(II)/diethylmalonate(-1,-2) complexes

“…The resultant solution was stirred for 1 h, during which time a microcrystalline solid formed. The precipitate was collected by filtration, washed with cold EtOH (2 Â 1 ml) and Et 2 O (3 Â 2 ml), and dried in a vacuum desiccator over P 4 …”

“…The formation microequilibria of the proton, Ca 2+ and Mg 2+ binding to Gla and its derivatives have been studied [4]; the calciumbinding constants obtained clearly indicate that two or three dicarboxylate moieties and/or additional stabilizing factors are required for the formation of high-affinity binding sites in blood-clotting proteins [1]. Several scientists [5] have suggested that a principal role for Gla is in the discrimination between Ca 2+ and Mg 2+ .…”