Reactive oxygen species are a major cause of damage occurring in ischemic tissue after reperfusion. During reperfusion transitional metals such as iron are required for reactive oxygen species to mediate their major toxic effects. Xanthine oxidase is an important source of reactive oxygen species during ischemia-reperfusion injury, but not in all organs or species. Because cytochrome P-450 enzy...

Water binding to several Mg(2+) chelates, ethylenediamine, ethylenediamine-N,N'-diacetate, porphyrin, chlorophyll a and bacteriochlorophyll a, to form five- and six-coordinate complexes is studied by means of density functional theory. The results obtained for magnesium chelates are compared with the properties of the respective aqua complexes and the influence of the permittivity of environmen...

Coordination exchange processes tend to dominate the solution state behaviour of lanthanide chelates and generally prohibit the study of small conformational changes. In this article we take advantage of coordinatively rigid Eu(3+) chelates to examine the small conformational changes that occur in these chelates as water dissociatively exchanges in and out of the inner coordination sphere. The ...

The active site Fe(III) of protocatechuate 3,4-dioxygenase (3,4-PCD) from Pseudomonas putida is ligated axially by Tyr447 and His462 and equatorially by Tyr408, His460, and OH(-). Tyr447 and OH(-) are displaced as protocatechuate (3,4-dihydroxybenzoate, PCA) chelates the iron and appear to serve as in situ bases to promote this process. The role(s) of Tyr408 is (are) explored here using mutant ...

The electronic structure of model platinum-guanine and tin-guanine adducts has been studied both at semiempirical level and by using ab initio methods at the correlation level. The possible binding energies have been evaluated and most probable strustures were determined. In all cases the binding enegies of the gaseous tin chelates are rather large. The stabilizing role of the hydrogen bonds ha...

Hydrazine derived compounds and its Co(II), Cu(II) and Ni(II) chelates having the same metal ion but different anions (e.g., nitrate, sulphate, oxalate and acetate) have been synthesised and characterised by their physical, spectral and analytical data. In order to evaluate the participating role of anions in the antibacterial activity, these synthesised ligands and its metal chelates have been...

The hydroxamic acid siderophore ferrioxamine B [FeIII(HDFB)+] and the iron complex of diethylenetri-aminepentaacetic acid [FeIII(DTPA)2-] protected mice against death by septic shock induced by Corynebacterium parvum + lipopolysaccharide. Although FeIII(DTPA)2- was somewhat more effective than FeIII(HDFB)+, the iron-free ligand H4DFB+ was significantly more effective than DTPA. The hydroxamic a...

β-thalassemias are heterogeneous hereditary anemias characterized by a reduced output of β-globin chains. The disease is most frequent in the temperate regions of the world, where it represents an important health problem. In the last decades, several programs, aimed at controlling the birth rate of thalassemia newborns by screening and prenatal diagnosis of populations with high risk of β-thal...

Site-specific cleavage of proteins with metal chelates is an approach for designing artificial proteolytic reagents that are directed by proximity to a peptide bond rather than by an amino acid residue type. In the presence of ascorbate and H2O2, an iron chelate attached to Cys-212 of the enzyme human carbonic anhydrase I quickly cleaved the protein between residues Leu-189 and Asp-190 to produ...

In this thesis, interaction of ferritin with transition metal ions and chelates is studied. First, a simple method for synthesizing gold nanoparticles stabilized by horse spleen apoferritin (HSAF) was reported using NaBH4 or 3-(N-morpholino)propanesulfonic acid (MOPS) as the reducing agent. The average particle diameters were 3.6 and 15.4 nm for NaBH4-reduced and MOPS-reduced Au-HSAF, respectiv...