Dissociation binding

The conditional stability constants (log K<.) obtained for copper with humic compounds extracted from soils and natural waters are invariably greater than those for other transition metals (see Table IV). This is expected from the enhanced levels of crystal field stabilisation energy which result fi-om the splitting of the 3d electronic orbitals on Cu by an octahedral field (Mackay and Mackay, 1969). The divei ence in the values of log Kc shown in Table IV, may, in part, have arisen from intrinsic variations in the copper-binding properties of the various humic samples. However, these deviations may also be explained in terms of the different experimental conditions employed (pH, ionic strength, temperature, for example) and the assumptions made in the calculations. For example, an increase in the pH will enhance the availability of dissociated binding sites (see Section 6) which are then free to participate in further complexation of copper and... 

Ceria is an easily reducible oxide, and any redox pretreatment strongly affects the nature of the surface hydroxyl groups. Cerium oxide has been the subject of detailed DFT calculations, and the results were recendy summarized (69 f). It was noted that H2O molecules strongly and dissociatively bind on oxygen vacancy sites and the dissociative adsorption of water is favored on defective surfaces. Even at low temperature, water dissociates on partially reduced ceria (692). It was reported that surface hydroxyls on ceria are also produced as a result of H2 dissociation (509). 

Biological [41] and synthetic [42] molecular walkers can often be described in terms of a three-state mechanism shown that involves a mechanical transition L — R along with two energy-driven processes, E L and E R, in which one of the heads dissociates/binds to the molecular track as shown in Fig. 12. This mechanism can also be written as a triangle reaction ... 

Aside from the amyloid based model for AD, iron was also demonstrated to enhance phosphorylation of Tau and the formation of the neurofibrillary tangles associated with the AD brain [10]. In this report a novel trivalent cationic chelator, Feralex, effectively dissociated binding of aluminum and iron to hyperphosphorylated Tau (neurofibrillary tangle) pertinent to its use as a therapeutic agent for AD. 

Shin, R., et al., A novel trivalent cation chelator Feralex dissociates binding of aluminum and iron associated with hyperphosphorylated tau of Alzheimer s disease. Brain Res, 2003.961(1) p. 139-46. 

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