Bioanalytical interaction studies executed by preincubation affinity capillary electrophoresis

Østergaard, Jesper; Heegaard, Niels H. H.

doi:10.1002/elps.200600047

Cited by 58 publications

(57 citation statements)

References 186 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was most likely caused by dissociation of Cu(II) from the peptide when the sample was injected into the electrophoresis buffer and electrophoresis was applied. Results based on stopped-flow spectroscopy (27) show that the dissociation rate constant of Cu(II) from the A␤-Cu(II) complex is ϳ0.1 s Ϫ1 meaning that the complex had completely dissociated at the time (about 9 min) of detection (60).…”

Section: Fibrils Were Not Detected Initially In the Absence Of Cu(ii)mentioning

confidence: 99%

Cu(II) Mediates Kinetically Distinct, Non-amyloidogenic Aggregation of Amyloid-β Peptides

Pedersen

Østergaard

Rozlosnik

et al. 2011

Journal of Biological Chemistry

Self Cite

118

160

View full text Add to dashboard Cite

Cu(II) ions are implicated in the pathogenesis of Alzheimer disease by influencing the aggregation of the amyloid-␤ (A␤)peptide. Elucidating the underlying Cu(II)-induced A␤ aggregation is paramount for understanding the role of Cu(II) in the pathology of Alzheimer disease. The aim of this study was to characterize the qualitative and quantitative influence of Cu(II) on the extracellular aggregation mechanism and aggregate morphology of A␤ 1-40 using spectroscopic, microelectrophoretic, mass spectrometric, and ultrastructural techniques. We found that the Cu(II):A␤ ratio in solution has a major influence on (i) the aggregation kinetics/mechanism of A␤, because three different kinetic scenarios were observed depending on the Cu(II):A␤ ratio, (ii) the metal:peptide stoichiometry in the aggregates, which increased to 1.4 at supra-equimolar Cu(II):A␤ ratio; and (iii) the morphology of the aggregates, which shifted from fibrillar to non-fibrillar at increasing Cu(II):A␤ ratios. We observed dynamic morphological changes of the aggregates, and that the formation of spherical aggregates appeared to be a common morphological end point independent on the Cu(II) concentration. Experiments with A␤ 1-42 were compatible with the conclusions for A␤ 1-40 even though the low solubility of A␤ 1-42 precluded examination under the same conditions as for the A␤ 1-40 . Experiments with A␤ 1-16 and A␤ 1-28 showed that other parts than the Cu(II)-binding His residues were important for Cu(II)-induced A␤ aggregation. Based on this study we propose three mechanistic models for the Cu(II)-induced aggregation of A␤ 1-40 depending on the Cu(II):A␤ ratio, and identify key reaction steps that may be feasible targets for preventing Cu(II)-associated aggregation or toxicity in Alzheimer disease.Extracellular cerebral plaques composed mainly of amyloid ␤-peptide (A␤) 1-40 and 1-42 fibrils are a histopathological hallmark of Alzheimer disease (AD) 3 (1, 2). These plaques contain elevated levels of metals, in particular zinc and copper (3). Also, it has been shown that these metal ions can promote the aggregation of A␤ in vitro (4, 5). This implies a key role of the metal ions in the A␤-mediated pathology of AD (6), although the subject is still under much debate (7,8), and a role of amyloid-independent pathways in AD neurodegeneration have recently been reviewed (9).Specifically regarding the role of metal ions in the amyloidmediated pathology of AD, it is believed that Zn(II) acts as a neuroprotector (10, 11), whereas Cu(II) is considered to mediate neurotoxicity (12)(13)(14). The latter effect is thought to occur through early stage soluble A␤ and A␤-Cu oligomeric intermediates (15-18) that may be involved in the formation of reactive oxygen species (6). It was discovered that Cu(II) may be released postsynaptically at glutamatergic synapses in hippocampus (19,20), the site for initial A␤ deposition in AD. This provides an explanation for how Cu(II) can interact with A␤. Seemingly in contrast to the support for the neurotoxic effects of Cu(II),...

show abstract

Section: Fibrils Were Not Detected Initially In the Absence Of Cu(ii)mentioning

confidence: 99%

Cu(II) Mediates Kinetically Distinct, Non-amyloidogenic Aggregation of Amyloid-β Peptides

Pedersen

Østergaard

Rozlosnik

et al. 2011

Journal of Biological Chemistry

Self Cite

118

160

View full text Add to dashboard Cite

show abstract

“…Characterization of the binding process by estimating the binding parameters, such as binding constant, is essential in understanding drug-protein interactions in the biological system. Meanwhile, the measurement of the binding constant of a drug to blood proteins is of utmost importance for drug discovery and preclinical studies of drug candidates in pharmaceutical research (Barri et al, 2008;Østergaard and Heegaard, 2006).…”

Section: Introductionmentioning

confidence: 99%

Study of nobiletin binding to bovine serum albumin by capillary electrophoresis–frontal analysis and circular dichroism

Deng

et al. 2010

Biomedical Chromatography

View full text Add to dashboard Cite

A very recent epidemiological study provided strong support for nobiletin (NOB) as a potential candidate chemopreventive agent against cancer. From the pharmacology point of view, drug-protein interactions are determining factors in therapeutic, pharmacodynamic and toxicological drug properties. In this work, for the first time, detection of NOB at near-physiological conditions was accomplished by means of capillary electrophoresis-frontal analysis (CE-FA), and then the binding constants of NOB with bovine serum albumin (BSA) at the same conditions were determined. Complexation of NOB-BSA led to a decrease of the height for free NOB with increasing concentration of BSA. These results revealed the presence of a single class of binding site on BSA, and provided the binding constant of 10(3)/m, showing the strong affinity of NOB for BSA. Furthermore, circular dichroism spectra showed that, when the molar ratio of NOB to BSA was up to 2:1, NOB did not affect the overall protein conformation significantly and the protein thus retained a native-like structure. These results may provide important information for preclinical studies of nobiletin in pharmaceutical research.

show abstract

“…CE has been established as an efficient micromethod for studying molecular interactions [23][24][25][26][27][28]. Different formats for conducting affinity CE have been developed; their pros and cons have been discussed previously [23,26,[29][30][31][32][33]. The recognized advantages associated with the capillary electrophoresis frontal analysis (CE-FA) format (and affinity CE generally) are relatively short analysis times, simple method development, low sample consumption, and ease of automation.…”

Section: Introductionmentioning

confidence: 99%

Binding of Low-Molecular-Weight Cationic Ligands to Chondroitin Sulfate as Studied by Capillary Electrophoresis Frontal Analysis

Østergaard

Jensen²,

Larsen³

et al. 2009

TOACJ

View full text Add to dashboard Cite

The feasibility of capillary electrophoresis frontal analysis for the study of low-molecular-weight ligandchondroitin sulfate interactions was investigated. The interaction of the 7 cationic ligands (lidocaine, propranolol, scopolamine, N-methyl scopolamine, N-butyl scopolamine, 2-propylisochinolinium, and methyl viologen) with the glycosaminoglycan chondroitin sulfate was investigated in 0.067 M phosphate buffer, pH 7.4, at 25 o C. A frontal analysis method with a short analysis time, suitable for ranking ligands according to degree of complexation for chondroitin sulfate was developed. The double charged ligand methyl viologen possessed the highest affinity for chondroitin sulfate. Linear binding isotherms were obtained and apparent association constants were determined. Capillary electrophoresis frontal analysis may be an attractive tool for characterization of ligand-glycosaminoglycan interactions.

show abstract

Bioanalytical interaction studies executed by preincubation affinity capillary electrophoresis

Cited by 58 publications

References 186 publications

Cu(II) Mediates Kinetically Distinct, Non-amyloidogenic Aggregation of Amyloid-β Peptides

Cu(II) Mediates Kinetically Distinct, Non-amyloidogenic Aggregation of Amyloid-β Peptides

Study of nobiletin binding to bovine serum albumin by capillary electrophoresis–frontal analysis and circular dichroism

Binding of Low-Molecular-Weight Cationic Ligands to Chondroitin Sulfate as Studied by Capillary Electrophoresis Frontal Analysis

Contact Info

Product

Resources

About