Charge neutralization resolution enhancement

This chapter collates data from various sources so that the roles the metal ions play in the enzymic manipulation of phosphate derivatives might be assessed. The use of model systems has allowed an estimation of the degree of activation (rate enhancement) expected for particular modes of metal ion-phosphate derivative interaction. In the enzymic systems, some of the roles proposed from the model systems seem to be especially relevant and it is no coincidence that the multiple metal ions required for high activity in the models are reflected in the clusters of metal ions in the reaction centers of some enzymes apparent when high-resolution structural analyses have been carried out. Clearly, charge neutralization, polarization, intramolecular nucleophiles, and effects on the leaving groups are all pertinent aspects for the metal ion s role in the natural systems. They are certainly important in the model systems. Moreover, much, but not all, of the rate enhancement in the metalloenzymes can be accounted for by these effects. Also, the role of intramolecular acids and bases in the enzyme systems is probably important. Certainly, the structures imply intimate... 

Micellar electrokinetic capillary chromatography (MECC) is a mode of CE similar to CZE, in which surfactants (micelles) are added to the buffer system. Micellar solutions can be used to solubilize hydrophobic compounds that would otherwise be insoluble in water. In MECC the micelles are used to provide a reversed-phase character to the separation mechanism. Although MECC was originally developed for the separation of neutral species by capillary electrophoresis, it has also been shown to enhance resolution in the analysis of a variety of charged species.16... 

DUAL CYCLODEXTRIN SYSTEMS Applying Only One CD in CE occasionally is insufficient to completely resolve chiral compounds as can be seen above. Therefore, either another CD or a combination of two CDs in dual systems can be tested to enhance both enantioselectivity and resolution. The second CD then provides enantioselectivity itself, competes with the other CD, or provides a differential migration rate. A dual system usually combines a neutral and a charged CD, or more rarely either two charged or two neutral CDs. CDs might also be combined with carbohydrates, ion-pairing reagents, surfactants, crown ethers,... 

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