Evaluation of Zn- and Cu-Binding Affinities of Native Cu,Zn-SOD1 and Its G93A Mutant by LC-ICP MS.

The tight binding of Cu and Zn ions to superoxide dismutase 1 (SOD1) maintains the protein stability, associated with amyotrophic lateral sclerosis (ALS). Yet, the quantitative studies remain to be explored for the metal-binding affinity of wild-type SOD1 and its mutants. We have investigated the demetallation of Cu,Zn-SOD1 and its ALS-related G93A mutant in the presence of different standard metal ion chelators at varying temperatures by using an LC-ICP MS-based approach and fast size-exclusion chromatography.

Integrated isolation and quantitative analysis of exosome shuttled proteins and nucleic acids using immunocapture approaches.

Clinical implementation of exosome based diagnostic and therapeutic applications is still limited by the lack of standardized technologies that integrate efficient isolation of exosomes with comprehensive detection of relevant biomarkers. Conventional methods for exosome isolation based on their physical properties such as size and density (filtration, ultracentrifugation or density gradient), or relying on their differential solubility (chemical precipitation) are established primarily for processing of cell supernatants and later adjusted to complex biological samples such as plasma. Though still representing gold standard in the field, these methods are clearly suboptimal for processing of routine clinical samples and have intrinsic limits that impair their use in biomarker discovery and development of novel diagnostics.

Affinity of zinc and copper ions for insulin monomers.

Zinc is an essential trace element involved in the correct packing and storage of insulin. Total zinc content in the pancreatic β-cells is among the highest in the body and changes in the Zn(2+) levels have been found to be associated with diabetes. The most common form of the Zn-insulin complex is a hexamer containing two zinc ions.

Zn(II) ions co-secreted with insulin suppress inherent amyloidogenic properties of monomeric insulin.

Insulin, a 51-residue peptide hormone, is an intrinsically amyloidogenic peptide, forming amyloid fibrils in vitro. In the secretory granules, insulin is densely packed together with Zn(II) into crystals of Zn(2)Insulin(6) hexamer, which assures osmotic stability of vesicles and prevents fibrillation of the peptide. However, after release from the pancreatic beta-cells, insulin dissociates into active monomers, which tend to fibrillize not only at acidic, but also at physiological, pH values.