Binding studies sulfate

Crystallographic analysis of a number of PNP inhibitor complexes revealed significant displacement of the inhibitors. These displacements appear to be the result of close contacts between the inhibitor and the ion in the phosphate binding site. Sulfate ions occupy the phosphate site in PNP crystals as they are grown from ammonium sulfate solution. These inhibitors were more potent when the binding was measured in 1 mMphosphate solution rather than in 50 mMphosphate. Kinetic studies showed that these inhibitors were competitive not only with inosine but also with phosphate, in keeping with the above observation. 

This section will cover some of the less popular analytes for which guani-dinium-based receptors have been reported. These analytes include flavins, nitronates, carbonates, sulfates, squarates, and lactones. Some of the receptors discussed above have been used to study these analytes as well however, their primary purpose was for recognition of the targets listed above. For instance, even though the first report of receptor 43 dealt with monitoring the induced helicity upon binding of sulfate counterions, the purpose of the design was to bind helical biomacromolecules. 

Another structural motif effective in binding anions is that of two face-to-face 1,3,5-trisubstituted benzenes with bridges containing amines (12). These receptors were observed to bind small anions with some selectivity. In the majority of binding studies, monovalent species such as nitrate and chloride bind more weakly (log Kg2.5) compared to dianions such as sulfate (log Ks 6.0). This structural motif was expanded even further in the elegant azaparacyclophane (13). At pH 4, this cubane is tetraprotonated and binds anionic fluorescent molecules such as l-anilinonaphthalene-8-sulfonate (ANS). ... 

Moderate sulfotransferase activity Very weak activity Sex differences noted Requires PAPS DNA and RNA binding studied Unlike V-OH-AAF, no increase in nucleic acid binding observed in presence of sulfate... 

S.R. Gratz, A.M. Stalcup, Enantiomeric separations of terbutaline by CE with a sulfated P-cyclodextrin chiral selector A quantitative binding study. Anal Chem, 70 5166-5171, 1998. 

A bis-cyclopeptide covalent capsule 154 for selective binding of sulfate dianion has been prepared in [116] using copper(I)-catalyzed click reaction-cycloaddition of the corresponding azide to alkyne ligand syntones by Scheme 2.103 and characterized using NMR and X-ray diffraction data. Thermodynamics and kinetics of the encapsulation reaction for this guest have been studied by ITC and temperature-depended H- H NOESY NMR methods, respectively. 

The demonstration that H. pylori binds heparan sulfate [16] was further studied by inhibition by various compounds, and heparin-binding proteins were detected on bacterial cells [37]. Such proteins apparently facilitate bacterial phagocytosis by polymorphonuclear cells, since bacteria with a strong heparan sulfate binding were... 

Heparan sulfate proteoglycans and the coreceptors have been localized predominantly to the basolateral surface of WD HAE cells (47), which correlates with preferential transduction of these cells when vector is applied to the basolateral membrane relative to the apical membrane. However, binding studies of radiolabeled AAV-2 have shown only a four- to sevenfold reduction in binding to the cal membrane of WD HAE in culture as compared to the basal membrane. Because gene transfer efficiency was 200- fold greater following basal application than for luminal qiplication, the existence of apical membrane receptors for AAV-2 that are not functional for vector expression have been proposed (47,94). 

Bloor D M, Wan-Yunis W M Z, Wan-Badhi W A, Li Y, Hoizwarth J F and Wyn-Jones E 1995 Equilibrium and kinetio studies assooiated with the binding of sodium dodeoyl sulfate to the polymers poly(propylene oxide) and ethyl-(hydroxyethyl)oellulose Langmuir 3395-400... 

For the investigation of molecular recognition in micelles, adenine derivatives and positively charged (thyminylalkyl)ammonium salts such as shown in Figure 30 were prepared, which were solubilized in sodium dodecyl sulfate (SDS) solutions. Nmr studies have shown that binding occurs in a 1 1 molar ratio in the interior of the micelles as illustrated in Figure 30 (192). 

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