Glutathione (GSH) is a natural tripeptide composed of glutamic acid (Glu), cysteine (Cys), and glycine (Gly), which is a compound containing a sulfhydryl group (SH). It is an important antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione reacts with 5,5’-dithiobis-2-nitrobenzoic acid (DTNB) to form a yellow product, with maximum absorption at 412 nm.

Glutathione S-transferase (GST) is a family of proteins with many physiological functions, which mainly exists in the cytoplasm. GST is an important part of detoxification enzyme system in the body. It mainly catalyzes various chemical substances and their metabolites to covalent bond with the sulfhydryl group of GSH. So that electrophilic compounds become hydrophilic substances, which are easy to be excreted from bile or urine, so as to degrade various potentially toxic substances in the body and expel them out of the body. Therefore, GST plays an important biological role in protecting cells from electrophilic compounds.

In addition, because GST has the activity of GSH-Px, it is also called non-se GSH-px and has the function of repairing macromolecular such as DNA and protein damaged by oxidation. Note that GST-catalyzed reactions reduce GSH content but do not increase GSSG content.

GST catalyzed the binding of GSH with CDNB, and the light absorption peak wavelength of the binding product is 340 nm. Calculate the GST activity by measuring the absorbance rising rate at the wavelength of 340 nm.

Oxidized Glutathione (GSSG) is an oxidized form of glutathione (GSH), also known as dithione glutathione, formed by the oxidation of two molecules of glutathione. GSSG is reduced to GSH by glutathione reductase, so most of the body is in the reduced form. The determination of GSH and GSSG content and the ratio of GSH/GSSG in cells can reflect the redox status of cells. This kit utilizes the reaction of glutathione and (5, 5'-dithiobis-2-nitrobenoic acid, DTNB) to produce 5-thio-2-nitrobenzoic acid, which has the largest absorption at a wavelength of 412 nm, and 2-Vinylpyridine inhibits reduced glutathione in the original samples, and then uses glutathione reductase to reduce GSSG to GSH, determining the content of Oxidized Glutathione.

Lipid peroxide is produced by the action of oxygen free radicals on unsaturated fatty acid, then resolves to compounds, including malondialdehyde (MDA), the level of lipid peroxidation can be showed by detecting the level of MDA. Under acidic and high temperature conditions, the brown red 3,5,5-three methyl sulfamethoxazole-2,4-two ketone was synthesized with MDA and thiobarbituric acid (TBA) taking place condensation reaction, the largest absorption wavelength is 532 nm. The content of lipid peroxidation can be estimated after colorimetric. But the soluble sugar will disturb the detection, the production (color reaction of soluble sugar with TBA) have absorption wavelength in 450 nm and 532 nm. In this kit, the MDA content is calculated by the difference between the absorbance at 532 nm, 450 nm and 600 nm. Due to the effect of sucrose in plant tissues and glucose in animal tissues, this kit have two computational formulas for sucrose and glucose.

Catalase (CAT) exists widely in animal, plant, microorganism and cultured cells, which is the main enzyme of clearing H₂O₂.
H₂O₂ has characteristic absorption peaks at 240nm, CAT resolves H₂O₂, make the absorbance of reagent at 240nm decreases, and the activity of CAT can be calculated according to the change rate of absorbance.

Superoxide dismutase (SOD, EC 1.15.1.1) is a metalloenzyme widely present in living organisms. It is an important oxygen radical scavenger that catalyzes the deuteration of superoxide anions and produces H₂O₂ and O₂. SOD is not only a superoxide anion scavenging enzyme, but also a major enzyme producing H₂O₂, which plays an important role in the biological antioxidant system.

Superoxide anion (O₂⁻) is produced by the xanthine and xanthine oxidase reaction system, and O₂⁻-reducible nitroblue tetrazolium produces blue formazan, which absorbs at 560 nm; SOD can remove O₂⁻, thereby inhibiting the formation of formazan; the deeper the blue of the reaction solution, the lower the SOD activity, and the higher the activity.

Peroxidase (EC 1.11.1.7) is an enzyme found broadly in biological systems that utilizes hydrogen peroxide in the oxidation of various substrates. The MOLEQULE-ON POD Assay Kit provides a simple and direct procedure for measuring peroxidase activity in a variety of biological samples.
The reaction is 2 phenolic donor + H₂O₂ = 2 phenoxyl radical of the donor + 2 H₂O. The product has an absorption at 470 nm.

The Reactive Oxygen Species (ROS) Detection Kit offered by MOLEQULE-ON provides the key reagents necessary for the detection of ROS in live cells. The assay is based on H₂DCFDA, a reliable fluorogenic marker for ROS in live cells. We also provide the common inducer of ROS production Reactive oxygen control (Component B, Rosup), as a positive control. Using this combination of dyes according to the optimized protocol provided, oxidatively stressed and non-stressed cells are reliably distinguished by fluorescence microscopy. Generation of ROS is inevitable for aerobic organisms, and, in healthy cells, occurs at a controlled rate. Under conditions of oxidative stress, ROS production is dramatically increased, resulting in subsequent alteration of membrane lipids, proteins, and nucleic acids. Oxidative damage of these biomolecules is associated with a variety of pathological events including atherosclerosis, carcinogenesis, ischemic reperfusion injury, neurodegenerative disorders and with aging.

We utilize H₂DCFDA, a unique cell-permeable fluorogenic probe, compatible with phenol red, FBS and BSA to detect reactive oxygen species in live cells. Upon the cell entry, H₂DCFDA is modified by cellular esterases to form a non-fluorescent H₂DCF. Oxidation of H₂DCF by intracellular ROS yields a highly fluorescent product that can be detected by FACS, microplate reader, or fluorescence microscope (Ex/Em 495/529 nm). The fluorescence intensity is proportional to the ROS levels. Our kit provides a simple and specific assay for the real-time measurement of global levels of ROS in living cells. We include sufficient reagents to perform 100 assays and a common ROS inducer as a control for measurement of ROS levels or antioxidant activity with high sensitivity, specificity and accuracy.

Caspase-3 is the main terminal protease in the process of apoptosis and also the most studied Caspase. It activates pro-caspase-2,6,7,9, hydrolyzes various key apoptotic proteins, such as PARP, makes chromatin condensation, apoptotic body formed and nuclear DNA fragmentation. The caspase 3 colorimetric assay is based on the hydrolysis of the peptide substrate acetyl-Asp-Glu-ValAsp p-nitroanilide (Ac-DEVDpNA) by caspase 3, resulting in the release of the p-nitroaniline (pNA) moiety. P-Nitroaniline has a high absorbance at 405 nm. The activity of Caspase can be calculated by detecting pNA. This kit is suitable for mammalian tissue and cell.

Total antioxidant capacity is made up primarily for antioxidants and antioxidant enzymes. It can detect total antioxidant capacity of all kinds of antioxidant like serum, plasma, cell or tissue lysate and others.
The total antioxidant capacity can be reacted by reducting Fe³⁺-three pyridine three azine (Fe³⁺-tptz) to blue Fe²⁺-tptz in acidic environment.