Open AccessJournal Article
Free radicals and protein degradation in human red blood cells.
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TLDR
It is proposed that human RBC proteins can be oxidatively damaged by certain free-radicals, and that the oxidized proteins are specifically recognized and degraded by intracellular proteinolytic systems.Abstract:
Human red blood cells (RBC) were exposed to oxygen-based free-radicals, and other activated oxygen species generated during incubation with xanthine plus xanthine oxidase (X+XO). Oxygen-radical exposure induced up to 30 fold increases in human RBC protein degradation, compared to 12 fold increases in rabbit RBC protein degradation. Protein degradation increased as a function of X+XO, but demonstrated saturation kinetics at higher XO concentrations. The presence or absence of an energy substrate (glucose) had no effect on protein degradation, indicating the possible role of ATP-independent proteinolytic systems. It is proposed that human RBC proteins can be oxidatively damaged by certain free-radicals, and that the oxidized proteins are specifically recognized and degraded by intracellular proteinolytic systems.read more
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Free radical-mediated oxidation of free amino acids and amino acid residues in proteins.
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Degradation of oxidized proteins by the 20S proteasome.
TL;DR: New experiments indicate that conditional mutational inactivation of the E1 ubiquitin-activating enzyme does not affect the degradation of oxidized proteins, further strengthening the hypothesis that oxidatively modified proteins are degraded in an ATP-independent, and ubiquit in-dependent, manner by the 20S proteasome.
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Protein oxidation and peroxidation.
TL;DR: In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux as discussed by the authors.
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Intracellular proteolytic systems may function as secondary antioxidant defenses: An hypothesis
TL;DR: Evidence is presented to suggest that proteolytic systems (of proteinases, proteases, and peptidases) may function to prevent the formation or accumulation of oxidatively damaged protein aggregates and to prevent a wide variety of potentially toxic consequences.
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Protein oxidation and cellular homeostasis: Emphasis on metabolism.
Valentina Cecarini,Jillian Gee,Evandro Fioretti,Manila Amici,Mauro Angeletti,Anna Maria Eleuteri,Jeffrey N. Keller +6 more
TL;DR: A potential role for elevated levels of protein oxidation contributing to cellular dysfunction and oxidative stress via impacts on cellular metabolism is described.