Antioxidant activity applying an improved ABTS radical cation decolorization assay.

https://staff.blog.ui.ac.id/hsuryadi/files/2012/02/ROS_RNS.pdf

Free radicals and antioxidants in normal physiological functions and human disease

At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...

/pdf/free-radicals-in-the-physiological-control-of-cell-function-g3w3iyr0ph.pdf

Free Radicals in the Physiological Control of Cell Function

Living in an oxygenated environment has required the evolution of effective cellular strategies to detect and detoxify metabolites of molecular oxygen known as reactive oxygen species. Here we review evidence that the appropriate and inappropriate production of oxidants, together with the ability of organisms to respond to oxidative stress, is intricately connected to ageing and life span.

Oxidants, oxidative stress and the biology of ageing.

Photoperoxidation in isolated chloroplasts. I. Kinetics and stoichiometry of fatty acid peroxidation.

Publisher Summary Oxygen radicals are implicated as an important cause of oxidative modification of proteins which may lead to their rapid degradation. Among the various oxidative modifications of amino acids in proteins, carbonyl formation may be an early marker for protein oxidation. This type of alteration is characterized as metal-catalyzed oxidation of proteins. The molecular mechanisms of this type of protein oxidation are discussed in this chapter. Redox cycling cations, such as Fe 2+ or Cu 2+ can bind to cation binding locations on proteins and with the aid of further attack by H 2 O 2 or O 2 can transform side-chain amine groups on several amino acids into carbonyls. The most likely amino acid residues to form carbonyl derivatives are lysine, arginine, proline, and histidine. Metal-catalyzed oxidation of proteins is not necessarily the only mechanism by which carbonyls are introduced into proteins. The chapter discusses the physiological importance of protein oxidation. Increases in carbonyl levels are examined in several diseases, such as rheumatoid arthritis, ischemia-reperfusion injury to heart muscles, and muscle damage caused by exhaustive exercise.

Oxidative damage to proteins : spectrophotometric method for carbonyl assay

Reactive oxygen species (ROS) are implicated in the pathogenesis of a wide variety of human diseases. Recent evidence suggests that at moderately high concentrations, certain forms of ROS such as H202 may act as signal transduction messengers. To develop a better understanding of the exact mechanisms that underlie ROS-dependent disorders in biological systems, recent studies have investigated the regulation of gene expression by oxidants, antioxidants, and other determinants of the intracellular reduction-oxidation (redox) state. At least two well-defined transcription factors, nuclear factor (NF) kappa B and activator protein (AP) -1 have been identified to be regulated by the intracellular redox state. The regulation of gene expression by oxidants, antioxidants, and the redox state has emerged as a novel subdiscipline in molecular biology that has promising therapeutic implications. Binding sites of the redox-regulated transcription factors NF-kappa B and AP-1 are located in the promoter region of a large variety of genes that are directly involved in the pathogenesis of diseases, e.g., AIDS, cancer, atherosclerosis and diabetic complications. Biochemical and clinical studies have indicated that antioxidant therapy may be useful in the treatment of disease. Critical steps in the signal transduction cascade are sensitive to oxidants and antioxidants. Many basic events of cell regulation such as protein phosphorylation and binding of transcription factors to consensus sites on DNA are driven by physiological oxidant-antioxidant homeostasis, especially by the thiol-disulfide balance. Endogenous glutathione and thioredoxin systems, and the exogenous lipoate-dihydrolipoate couple may therefore be considered to be effective regulators of redox-sensitive gene expression. The efficacy of different antioxidants to favorably influence the molecular mechanisms implicated in human disease should be a critical determinant of its selection for clinical studies.

Lester Packer

Papers

Photoperoxidation in isolated chloroplasts. I. Kinetics and stoichiometry of fatty acid peroxidation.

Oxidative damage to proteins : spectrophotometric method for carbonyl assay

Antioxidant and Redox Regulation of Gene Transcription

alpha-Lipoic acid as a biological antioxidant.

Photoperoxidation in isolated chloroplasts. II. Role of electron transfer.