INVESTIGADORES
PENA liliana Beatriz
capítulos de libros
Título:
Protein oxidative modifications
Autor/es:
LB PENA; CE AZPILICUETA; MP BENAVIDES; SM GALLEGO
Libro:
Metal toxicity in plants: Perception, Signalling and Remediation
Editorial:
Springer-Verlag
Referencias:
Año: 2012; p. 207 - 225
Resumen:
Proteins are molecules especially susceptible to oxidative modifications owing to their abundance and reactivity to radicals. Amongst the protein oxidative (redox) changes, carbonylation of the molecules represent an irreversible process that conduce to the lost of protein functionality. A bulk of carbonylated proteins are produced s as a result of metal oxidative stress induction in plants. Besides, metal ions-catalyzed oxidation (MCO) systems have been especially used for the introduction of carbonyl groups in the protein molecules in vitro. The mechanism underlying protein carbonylation for redox active metals is the direct catalysis of ROS generation, while metals considered redox inactive act decreasing the antioxidant defence system. Despite protein carbonylation is associated with general and random processes; recent advances indicate a great degree of selectivity in the protein oxidation process. In turn, there are proteins, such as catalase, that respond to metal-induced oxidative stress by regulating the translation of isoforms and thus inducing the synthesis of new subunits less sensitive to oxidation. Further, the intracellular level of oxidized proteins is the product of a balance between the rate of oxidation and the rate of degradation of proteins. Metals can alter plant cell capacity for removing damaged proteins. As part of the proteolytic system, the 20S proteasome is responsible for the proteolysis of the carbonylated proteins. The 20S proteasome activity is regulated through oxidative modification of the proteasome itself, where a moderate 20S protein oxidation increases its activity, but a severe oxidative condition decreases it, concomitantly producing oxidized proteins accumulation. The widespread occurrence of protein modifications, regulated proteolysis, as well as the existence of regenerative mechanisms of oxidative modifications is presented.