Flavonoid Thiol Toxicity: What’s in a Group?

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Antioxidants are a direct consequence of the highly oxidizing environment (21% atmospheric dioxygen) in which we live on the third rock from the sun. The switch from anaerobic to aerobic metabolism during the evolution of the majority of organisms on this planet not only resulted in a more efficient liberation of energy from glucose (~30 [1] vs. 2 ATP), but came at a price, since dioxygen has several alter-egos. With two unpaired electrons, dioxygen is a typical free radical, albeit that its chemistry is constrained; however, all hell breaks loose when this constraint is lifted and various highly reactive oxygen species (ROS) are formed.

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The Proteasome Activator PA28γ and P53: It Takes Two to Tango, but Which One Takes the Lead?

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The phosphoprotein p53 was trivially named after the apparent molecular mass it runs on SDS-PAGE, i.e., 53-kilodalton (kDa). Ever since its discovery in 1979 by several groups simultaneously, this extraordinary protein has captured the imagination of life scientists. p53 is likely the most extensively studied protein in cell biological research. To underscore its importance, p53 has been called a “cellular gatekeeper” [1] or “the guardian of the genome” [2], and for a long time researchers believed that p53 was the universal master switch that defined cancer onset and progression. However, this turned out to be not entirely true. Nonetheless, at least half of all cancer types carry aberrations in the p53 gene (TP53). p53 acts as a decision nodule that organizes the cell’s response to stress. Continue reading