Toxicology Exam 3

Toxicology Exam 3 - A rsenic Chromium Cr(III) only toxic to...

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Arsenic - 1 st toxic metal for which a biochemical mechanism of action has been clearly elucidated - Elevated Plasma Pyruvate level arsenic covalently binds to a-lipoic acid with its 2 (- SH) groups and inactivates pyruvate dehydrogenase - Arsenate is substituted for phosphate produces an unstable acyl arsenate intermediate that rapidly hydrolyzes without ATP Chromium - Cr(III) only toxic to enzymes and DNA and not to cells - Cr(VI) toxic to cells, but not DNA or enzymes - So Cr(VI) can enter the cell by the anion carrier that transports sulfate across the membrane. Once inside the cell the Cr(VI) is reduced to Cr(III) which can then damag DNA and enzymes - cancer Cadmium - A cytoplasmic protein Metallothionein (MT) in the liver binds to Cd the Cd-MT complex is transported to renal proximal tubular(kindney) and it gets broken down and these products damage the renals of the kindney - MT- Metallothionein is a soluble cytoplasmic protein in liver which stores Zn and Cu; can bind 6 Cd ions
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Toxicology Exam 3 - A rsenic Chromium Cr(III) only toxic to...

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