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10 Cards in this Set
- Front
- Back
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Singlet oxygen will react instantly with whatever it encounters. Typically, it reacts with ?? to form ?? (p395)
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Lipid --> Lipid Peroxide
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Homolytic cleavage of hydrogen peroxide forms what? In the presence of Fe2+, it forms:
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Two hydroxyl radicals. In the presence of Fe2+, hydrogen peroxide is reduced to hydroxyl group (OH-) and a hydroxyl radical (OH*)
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see pg 396 for Hydroxyl Radical damage mechanism
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see pg 396 for Hydroxyl Radical damage mechanism
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Hydrogen peroxide is destroyed in two ways: name the enzymes and where they're located.
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Catalase - located in peroxisomes with a high Km
Glutathione peroxidase - located in cytosol with a low Km |
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What unique atom is in Glutathione Peroxidase?
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Selenium
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What is the most prevalent antioxidant? It's a tripeptide made of what?
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Glutathione (GSH). It is composed of glutamate, cysteine, and glycine
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As you know, GSH is composed of glutamate, cysteine, and glycine. Cysteine constantly needs to be replenished, however...why?
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Bc it in detox of xenobiotics, cysteine is attached to the xenobiotic - glutamate and glycine are released and the cysteine/xenobiotic complex is released in the urine.
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In what form is GSH ready to eliminate a oxidative stress? GSH or GSSH? What regenerates the reduced form?
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GSH is oxidized to GSSH. GSH is regenerated with NADPH
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Damaged Proteins and mRNAs are typically degraded rather than being repaired. The two exceptions are:
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1. GSH reduces protein disulfides back to dithiols.
2. Methionine Sulfoxide Reductase uses NADPH to reduce methionine sulfoxide back to methionine. |
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Know what Oxygen Enhancement Ratio means:
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It is the ratio of the radiation dose needed to kill a fixed percentage of cells in an anoxic (anaerobic) environment to the radiation dose needed to kill the same percentage of cells in an oxygenated environment.
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