A miniaturized polymer electrospray-type interface is used to study metal-ion chelation with model peptides. Taking advantage of the intrinsic electrochemical behavior of electrospray, a sacrificial electrode is used to generate at the same time electrospray and transition-metal ions coming from the anodic dissolution of the electrode. The microspray interface provides enhanced mass transport d...

DNAzymes (or catalytic DNA) are cell-free biomolecular recognition tools with target recognition sequences for charged molecules such as metal ions, antibiotics, and pharmaceuticals. In this study, using in vitro selection, large populations (e.g., 1015) of random DNA sequences were used as the raw material for the selection of “catalytic or functional molecules” for Hg2 and As5 . From a random...

A structural investigation performed on adducts of human ubiquitin with group-12 metal ions reveals common preferential anchoring sites, the most populated one being His68; at higher metal ion concentration a second and a third site, close to the N-terminus of the protein, become populated and promote a polymorphic transition from orthorhombic to cubic form; Glu16 and Glu18, involved in the lat...

DNAzymes (or catalytic DNA) are cell-free biomolecular recognition tools with target recognition sequences for charged molecules such as metal ions, antibiotics, and pharmaceuticals. In this study, using in vitro selection, large populations (e.g., 10) of random DNA sequences were used as the raw material for the selection of ‘‘catalytic or functional molecules’’ for Hg2þ and As5þ. From a rando...

We propose new methodologies for stabilizing all-metal antiaromatic clusters like: Al4Li4. We demonstrate that these all-metal species can be stabilized by complexation with 3d-transition metals very similar to its organic counterpart, C4H4. Complexation to transition metal ions reduce the frontier orbital energies and introduces aromaticity. We consider a series of such complexes [η4(Al4Li4)-F...

A series of 5-dialkyl(aryl)aminomethyl-8-hydroxyquinoline dansylates were synthesized and their fluoroionophoric properties toward representative alkali ions, alkaline earth ions and transition metal ions were investigated. Among the selected ions, Fe3+ caused considerable quenching of the fluorescence, while Cr3+ caused quenching to some extent. The absence of any significant fluorescence quen...

The redox activity of metal ions can lead to the formation of highly reactive species that damage DNA, producing different oxidation products and types of damage depending upon the redox potentials of the DNA bases, formation of intermediate adducts, and identity of the reactive species. Other factors are also important in determining the degree of metal-mediated DNA damage, such as localizatio...

backgrounds and aims: the purpose of this study was to examine the effects of potassium, sodium and zinc metal ions on ammonium sulfate fraction of acid phosphatase activity of orange fruit. materials and methods: acid phosphatase was extracted and purified from orange fruit and then various samples as well as a control sample were prepared in vitro. in addition to substrates, ions of potassium...

A technique for preparing heterobimetallic frameworks with tunable metal sites is demonstrated by the synthesis of a new two-dimensional metal-organic framework that is constructed from tetra(4-carboxyphenyl)porphyrin and Cd(II) species. The solid can be prepared in the presence of other divalent transition metals to yield the same framework with the smaller metal ions occupying the porphyrin l...

The cyclic tetraimidazolium salt (H4-)(PF6)4 with flexible linkers between the imidazolium groups has been synthesized following a stepwise synthetic approach. In situ deprotonation of (H4-)(PF6)4 in the presence of different metal ions leads to complexes where the tetracarbene ligand shows differing coordination modes depending on the metal center. Due to its high flexibility the tetracarbene ...