We are addressing the puzzling metal ion specificity of Fe- and Mn-containing superoxide dismutases (SODs) [see C.K.Vance, A.-F. Miller. J. Am. Chem. Soc. 120(3) (1998) 461-467]. Here, we test the significance to activity and active site integrity of the Gln side chain at the center of the active site hydrogen bond network. We have generated a mutant of MnSOD with the active site Gln in the loc...

BACKGROUND Mitochondrial oxidative stress is a contributing factor in the etiology of numerous neuronal disorders. However, the precise mechanism(s) by which mitochondrial reactive oxygen species (ROS) modify cellular targets to induce the death of neurons remains unknown. The goal of this study was to determine if oxidative inactivation of mitochondrial aconitase (m-aconitase) resulted in the ...

Ten chromite ores from ophiolite complexes in SE Iran were analyzed mineralogically by XRD, chemically by XRF, and mineral chemistry by EPMA. The identified paragenesis of silicate minerals of chromite ores with the X-ray diffraction is pronounced differently. It consists of secondary phases formed as serpentine, Cr-containing chlorite (kaemmererite), chromic garnet (uarovite) with preserved pa...

The divalent metal-isocitrate site of pig heart NADP-specific isocitrate dehydrogenase can be located by affinity cleavage of the enzyme by Fe(2+)-isocitrate in the presence of O2, in analogy to the "chemical nuclease" action of DNA-binding drugs linked to Fe-EDTA. The enzyme is irreversibly inactivated and cleaved by Fe(2+)-isocitrate more rapidly than by Fe2+. Mn2+ prevents inactivation and c...

Analysis of RNA isolated from Pseudomonas aeruginosa PA103 and PAKS grown under Fe2+-limiting (0.08 microgram/ml) and Fe2+-sufficient (10 micrograms/ml) conditions demonstrated that exotoxin A (ETA) expression is regulated by Fe2+ at the level of transcription. S1 nuclease mapping revealed two 5' termini of the tox transcript, 89 base pairs (bp) (S1A) and 62 bp (S1B) 5' to the ETA initiation co...

Many commercial processes are available for the removal of H2S from gaseous streams. The desulfurization of gas streams using aqueous ferric sulfate solution as washing liquor is studied. Apart from sulfur, only H2O is generated in the process, and consequently, no waste treatment facilities are required. A distinct advantage of the process is that the reaction of H2S with is so rapid and compl...

She, Hongyun, Shigang Xiong, Min Lin, Ebrahim Zandi, Cecilia Giulivi, and Hidekazu Tsukamoto. Iron activates NFB in Kupffer cells. Am J Physiol Gastrointest Liver Physiol 283: G719–G726, 2002; 10.1152/ajpgi.00108. 2002.— Iron exacerbates various types of liver injury in which nuclear factor (NF)B-driven genes are implicated. This study tested a hypothesis that iron directly elicits the signalin...

Acceleration of the autoxidation of Fe2+ by apotransferrin or apolactoferrin at acid pH is indicated by the disappearance of Fe2+, the uptake of oxygen, and the binding of iron to transferrin or lactoferrin. The product(s) formed oxidize iodide to an iodinating species and are bactericidal to Escherichia coli. Toxicity to E. coli by FeSO4 (10(-5) M) and human apotransferrin (100 micrograms/ml) ...

Sickle erythrocytes have increased ferritin and increased molecular iron on the inner membrane leaflet, and we postulated that cytosolic labile iron is also elevated. We used the fluorescent metallosensor, calcein, and a permeant Fe2 chelator to estimate labile cytoslic Fe2 , and calcein plus an Fe3 chelator to estimate total cytosolic labile iron (Fe2 Fe3 ). We measured membrane nonheme iron b...