Every day, the cells of our body suffer damage caused by exogenous and endogenous factors. Oxidative stress, an important cellular damage factor, results from an imbalance between the production of cellular reactive oxygen species (ROS) and the inability of cells to detoxify the reactive intermediates or to repair the resulting damage.
Abcam has a variety of kits available to accurately measure metabolites involved in oxidative stress and cellular damage as well as the activity of antioxidant proteins involved in controlling oxidative damage.
Reactive oxygen species (ROS or free radicals) are chemically reactive molecules that form as natural by-products of the normal metabolism of oxygen or exogenous sources such as ionizing radiation. Examples of ROS are hydrogen peroxide, superoxide anion and hydroxyl radical. Due to their extremely unstable configuration, ROS molecules react quickly with other molecules to achieve a stable configuration, which in turn converts their interacting molecule into a radical.
ROS can react with molecules in every cellular compartment. Specifically, ROS is found to result in oxidative DNA damage and lipid peroxidation.
Oxidative DNA damage
Oxidative DNA damage is an inevitable consequence of cellular metabolism, with background levels of oxidative damage are observed in normal healthy cells. However, accumulation of oxidized bases can lead to mutagenesis and cytotoxicity if left uncontrolled; therefore, DNA repair mechanisms have evolved to prevent damage. An important mechanism that responds to oxidative DNA damage is the BER (base excision repair) pathway: BER is initiated by DNA glycosylases that recognize and remove the damaged bases, creating an AP (apurinic/apyrimidinic) site. AP sites are cleaved by AP endonucleases, resulting in single-strand break that is processed by either single nucleotide replacement or new nucleotide synthesis.
Lipid peroxidation is defined as the oxidation of membrane lipids. Lipid peroxides are very unstable and reactive, and they can react with purinic bases to form DNA adducts as well as cause permanent damage in the cell membrane.
Lipid peroxidation can occur by either autoxidation or by enzymatic peroxidation through lipoxygenases or cyclooxygenases. Lipooxygenases catalyze the reaction between O2 and polyunsaturated fatty acids such as arachidonic acid. Peroxidation of arachidonic acid generates hydroperoxides known as HpETES, which can be transformed into the hydroxy products HETES. Cyclooxygenases catalyze the addition of molecular oxygen to various polyunsaturated fatty acids leading to the formation of endoperoxides (PGG, PGH), intermediates in the transformation of fatty acids to prostaglandins.
|Product Name||Product Description||Product code|
|DNA damage - AP sites - Assay Kit (Colorimetric)||Colorimetric quantification of abasic (AP) sites in purified DNA samples|
|DNA damage - AP sites - Assay Kit (Cell-based)||Visualization of abasic (AP) sites in cells using fluorescence microscopy or FACS|
|DCFDA - Cellular Reactive Oxygen Species Detection Assay Kit||Quantification of ROS in cells using fluorescence microscopy, FACS or microplate reader|
|Cellular ROS/RNS Detection Assay Kit||Visualization of superoxide, nitric oxide and peroxynitrite production in cells using fluorescence microscopy|
|Cellular ROS/Superoxide Detection Assay Kit||Visualization of superoxide and total ROS production in cells using fluorescence microscopy or FACS|
|Cellular Superoxide Detection Assay Kit||Visualization of superoxide production in cells using fluorescence microscopy or FACS|
|Hydrogen Peroxide Assay Kit||Colorimetric or fluorometric quantification of hydrogen peroxide in biological samples|
|Cyclooxygenase (COX) Activity Assay Kit (Luminometric)||Luminometric quantification of COX1 & COX2 activity in biological samples in absence/presence of COX inhibitors|
|Lipid Hydroperoxide (LPO) Assay Kit|| |
Direct colorimetric quantification of lipid hydroperoxides through redox reactions with ferrous ions
|Lipoxygenase Inhibitor Screening Assay Kit||Colorimetric assay to assess compounds that can inhibit lipoxygenase activity|
|Lipid peroxidation (MDA) Assay Kit||Colorimetric or fluorometric quantification of lipid peroxidation through the by-product MDA|
|Myeloperoxidase (MPO) Inhibitor Screening Assay Kit||Fluorometric assay to assess compounds that can inhibit chlorination and peroxidation activity of MPO|
|Myeloperoxidase (MPO) Activity Assay Kit (Fluorometric)||Fluorometric quantification of myeloperoxidase activity|
|Myeloperoxidase (MPO) Activity Assay Kit (Colorimetric)||Colorimetric quantification of myeloperoxidase activity|
As shown above, excess ROS can lead to cellular damage in molecules such as DNA and lipids. To avoid this situation, mammalian cells have developed a variety of antioxidant defenses to counterbalance the presence of ROS and reduce the potential damage. These antioxidant systems include enzymes, macromolecules such as albumin and ferritin, and an array of small molecules, including ascorbic acid, α-tocopherol, reduced glutathione, bilirubin and uric acid.
The main enzymatic systems are superoxide dismutase, catalase and the glutathione system. These enzymes require co-factors such as selenium, iron and manganese for optimum catalytic activity, making these trace minerals essential for the effectiveness of cellular antioxidant mechanisms. Superoxide dismutases (SODs) catalyze the breakdown of superoxide into oxygen and hydrogen peroxide. Catalases are responsible of breaking down hydrogen peroxidase to water and oxygen. The glutathione enzymatic system includes glutathione peroxidases (GPX), glutathione-S-transferases (GST) and glutathione reductases (GR). GPXs catalyze the breakdown of lipid hydroperoxides and hydrogen peroxide, while GSTs catalyze conjugation of reduced glutathione to a wide range of hydrophobic electrophiles. GRs is essential for recycling the pool of oxidized glutathione back to reduced glutathione.
|Product Name||Product Description||Product code|
|Glutathione Detection Assay Kit (Fluorometric)||Fluorometric quantification of total glutathione (GSH & GSSG)|
|GST Activity Assay Kit (Fluorometric)||Fluorometric quantification of general glutathione-S-Transferase|
|GST Activity Assay Kit (Colorimetric)||Colorimetric quantification of general glutathione-S-Transferase|
|Total Antioxidant Capacity Assay Kit||Colorimetric quantification of antioxidant capacity through Cu2+ reduction|
|NAD/NADH Assay Kit||Colorimetric quantification of NAD/NADH production|
|NADP/NADPH Assay Kit||Colorimetric quantification of NADP/NADPH production|
|Superoxide Dismutase Activity Assay Kit (Colorimetric)||Colorimetric quantification of superoxide dismutase activity|
|Glutathione Reductase (GR) Assay Kit||Colorimetric quantification of glutathione reductase activity|
|Thioredoxin Reductase (TrxR) Assay Kit||Colorimetric quantification of thioredoxin reductase activity|
|Catalase Assay Kit|| |
Colorimetric or fluorometric quantification of catalase activity
|Glutathione Peroxidase Assay Kit||Colorimetric quantification of glutathione peroxidase activity|
|Intracellular GSH Assay Kit||Quantification of GSH levels in live cells using FACS to determine cell viability|
|Ascorbic Acid Assay Kit||Colorimetric or fluorometric quantification of ascorbic acid levels (0.1 - 10 nmol)|
|Ascorbic Acid Assay Kit (Biological Samples)||Colorimetric quantification of ascorbic acid levels (0.2 - 20 nmol)|
|Hydrogen Peroxidase Assay Kit (Cell-based)||Visualization of hydrogen peroxidase activity in live cells using fluorescence microscopy|
|GSH/GSSG Ratio Detection Assay Kit (Fluorometric - Green)||Fluorometric quantification of GSH/GSSG levels|
|Hydrogen Peroxidase Assay Kit (Fluorometric - Near Infrared)||Fluorometric quantification of hydrogen peroxidase activity|