Key features and details
- Assay type: Quantitative
- Detection method: Fluorescent
- Platform: Microplate reader
- Sample type: Other biological fluids, Serum, Urine
- Sensitivity: 10 µM
Product nameCysteine Assay Kit (Fluorometric)
Sample typeUrine, Serum, Other biological fluids
Species reactivityReacts with: Mammals, Other species
Cysteine Assay Kit (Fluorometric) (ab211099) provides a convenient method to quantify cysteine present in biological fluids such as serum and plasma. The assay principle is based on the cleavage of thiol group in reduced cysteine to produce that emits a stable signal that can be detected at Ex/Em = 365/450 nm. The amount of signal is directly proportional to the amount of total cysteine in the sample.
The reaction is specific and other thiol-based amino acids do not interfere with the assay. The assay can detect as little as 10 µM of Cysteine in a variety of samples.
This product is manufactured by BioVision, an Abcam company and was previously called K558 Cysteine Assay Kit (Fluorometric). K558-100 is the same size as the 100 test size of ab211099.
Cysteine (CYS, C) is a sulfhydryl-containing amino acid, and is an important structural and functional part of proteins. In animals, cysteine is synthesized from trans-sulfuration of homocysteine (HCY), which is itself derived from metabolism of the amino acid methionine. The enzyme Cystathionine β-Synthase catalyzes condensation of homocysteine with serine to form cystathionine, which is deaminated and hydrolyzed by Cystathionine β-lyase to form cysteine and α-ketobutyrate. Due to its nucleophilic nature, the thiol group of cysteine has numerous biological functions. The formation of disulfide linkages between the thiol groups of cysteine residues helps to stabilize the tertiary and quaternary structure of proteins. Cysteine, homocysteine and other aminothiols exist in plasma in reduced, oxidized, and protein-bound forms, interacting with each other through redox pathways.
Cysteine is the limiting precursor of the major intracellular antioxidant glutathione. The individuals with lower cysteine levels are more prone to damage from reactive oxygen species, which are generally removed either by thiols or by glutathione-linked enzymes. An elevated level of total cysteine also predicts adverse outcomes such as cardiovascular diseases and metabolic syndromes.
Storage instructionsStore at -20°C. Please refer to protocols.
Components Identifier 100 tests CYS Assay Buffer 1 x 25ml CYS Probe 1 x 500µl CYS Standard (10 µmole) 1 vial Enzyme Mix I 1 x 50µl Enzyme Mix II (500 mg) 3 vials HCY Blocker White cap 1 x 100µl Reducing Agent (20 mg) 2 vials
RelevanceCysteine is a naturally occurring amino acid which has a thiol group and is found in most proteins in small quantities. When exposed to air it oxidizes to form cystine, which is two cysteine molecules joined by a disulfide bond.
- (2R) 2 amino 3 sulfanyl propanoic acid
ab211099 has been referenced in 4 publications.
- Edwards DN et al. Selective glutamine metabolism inhibition in tumor cells improves antitumor T lymphocyte activity in triple-negative breast cancer. J Clin Invest 131:N/A (2021). PubMed: 33320840
- Neamah WH et al. AhR Activation Leads to Alterations in the Gut Microbiome with Consequent Effect on Induction of Myeloid Derived Suppressor Cells in a CXCR2-Dependent Manner. Int J Mol Sci 21:N/A (2020). PubMed: 33348596
- Suwannakul N et al. CD44v9 Induces Stem Cell-Like Phenotypes in Human Cholangiocarcinoma. Front Cell Dev Biol 8:417 (2020). PubMed: 32582701
- Kar S et al. Hydrogen Sulfide Ameliorates Homocysteine-Induced Cardiac Remodeling and Dysfunction. Front Physiol 10:598 (2019). PubMed: 31178749