The dephosphorylation of ATP was characterized by determining the dependence of the firstorder rate constant on pH in the absence and presence of Zn2+ and together with Zn2+ and 2,2'-bipyridyl. The Zn2+-accelerated reaction passes through a pH optimum at about 8. The decrease in the rate at higher pH is due to the formation of Zn(ATP) (OH)3-; this species is relatively in­ sensitive towards dep...

PURPOSE To examine the effects of Zn2+ on glutamate-induced neurotoxicity in cultured retinal neurons. METHODS Primary cultures obtained from fetal rat retinas (16 to 19 days gestation) were used. The neurotoxic effects of excitatory amino acids were quantitatively assessed using the trypan blue exclusion method. RESULTS A brief exposure of retinal cultures to glutamate or N-methyl-D-aspart...

Zinc ion fluorescence sensing and the binding properties of 4-methyl-2,6-bis(((phenylmethyl)imino)methyl)phenol (HL) have been investigated. It displays high selectivity for Zn2+ and can be used as zinc ion-selective luminescent probe for biological application under physiological conditions. The increase in emission in the presence of Zn2+ is accounted for by the formation of hexanuclear compl...

The bacterial heat shock protein Hsp33 is a redox-regulated chaperone activated by oxidative stress. In response to oxidation, four cysteines within a Zn2+ binding C-terminal domain form two disulfide bonds with concomitant release of the metal. This leads to the formation of the biologically active Hsp33 dimer. The crystal structure of the N-terminal domain of the E. coli protein has been repo...

In this work, we studied nonlinear dynamics and optical limiting (OL) effects of pulse trains in zinc porphyrins meso-tetrakis methylpyridiniumyl (Zn2+TMPyP) sulfonatophenyl (Zn2+TPPS) porphyrin J-aggregates. The environments were selected as aqueous solutions micelles sodium dodecyl sulfate (SDS) cetyltrimethyl ammonium bromide (CTAB). Our numerical results show that both Zn2+TMPyP Zn2+TPPS ar...

in this work, a novel method is described for the preconcentration of pb2+, cd2+ and zn2+ ions in environmental samples using uniform silanized mesopor (lus-1) functionalized by ethylenediamine groups as a new extractant. the determination of ions is done by inductively coupled plasma optical emission spectrometry (icp-oes). the extraction time and efficiency, ph and amount of adsorbent, minimu...

The synthesis and characterisation of the solvent-stabilized salt [Zn2(THF)6](2+)[BAr4(F)]2(-) (1) is presented, which features the dizinc dication [Zn2](2+) as an analogue of the calomel dication [Hg2](2+). The labile tetrahydrofuran (THF) solvate molecules of 1 can be readily substituted by other ligands. Reaction with the strong donor ligand PMe3 (Me = CH3) leads to the Zn(ii) complex [Zn(PM...

The role of Zn2+ in pre-organizing Abeta(10-21) amyloid formation is shown to preferentially alter the relative rate of fibril nucleation and to have little influence on fibril propagation. Fibril morphology, as determined by small angle neutron scattering (SANS) and transmission electron microscopy (TEM), was unchanged in the presence and absence of Zn2+ in Abeta(10-21), as well as in a series...

We demonstrate a novel route for hierarchical self-assembly of sub-micron sized peptide superstructures that respond to subtle changes in Zn2+ concentration. The self-assembly process is triggered by a specific foldingdependent coordination of Zn2+ by a de novo designed non-linear helix-loop-helix peptide, resulting in a propagating fiber formation and formation of spherical superstructures. Th...

A Zn2+ transport system encoded by the zntB locus of Salmonella enterica serovar Typhimurium has been identified. The protein encoded by this locus is homologous to the CorA family of Mg2+ transport proteins and is widely distributed among the eubacteria. Mutations at zntB confer an increased sensitivity to the cytotoxic effects of Zn2+ and Cd2+, a phenotype that suggests that the encoded prote...