Biochemical Effects of Mercury, Cadmium, and Lead

Eukaryotic initiation factor 2α kinase is a nitric oxide‐responsive mercury sensor enzyme: Potent inhibition of catalysis by the mercury cation and reversal by nitric oxide

“…Therefore, both Hg 2+ and NO may competitively regulate protein synthesis. Thiol anions form a complex with Hg 2+ [13] and S-NO species with NO [16][17][18][19][20]. Accordingly, we propose that protein synthesis is upregulated in cells contaminated with Hg 2+ as a result of Hg 2+ -thiol complex formation in HRI, which is reversed or reduced by NO due to the generation of S-NO species.…”

Catalytic properties of immobilized tannase produced from Aspergillus aculeatus compared with the free enzyme

“…This protection may be due to the following: 1) structureal changes in the enzyme molecule introduced by the immobilization procedure, lower the accessibility of inhibiting ions to the active site of the enzyme; and 2) the chelating effect of gelatin, which is known to be a very powerful chelating agent, especially when cross-linked with glutaraldehyde forming glutaraldehyde-cross-linked-gelatin particles (Kennedy, and Kalogerakis, 1980). Enzyme inactivation by heavy metals, including mercury (Hg 2+ ), proceeds by the reduction of the thiol group in cysteine residues, with the formation of mercaptides, or the reduction of disulfide bridges, leading to S-Hg-S bonds (Vallee and Ulmer, 1972). These results are in agreement with those obtained for immobilized tannase by Abdel-Naby et al (1999).…”

The levels of antioxidants and some trace metals in Nigerians that are occupationally exposed to chemicals

“…[14] Elevated concentration of hair chromium was reported in the tannery workers. [15] High level of cadmium in exposed individuals may interfere with cerebral pyruvate metabolism [16] and this may lead to thiamine deficiency, emphysema and proteinuria in the occupationally exposed individuals.…”