Tetrazoliumring

Tetrazoliumring refers to a five-membered heterocyclic ring system containing four nitrogen atoms and one carbon atom. Its chemical formula is C N4. The ring structure is planar and aromatic. Tetrazolium salts are compounds that contain this tetrazoliumring cation, often paired with an anion. These salts are widely used in biological and biochemical assays, particularly in the detection of cellular metabolic activity.

In these assays, tetrazolium salts act as electron acceptors. When a viable cell with active metabolic enzymes is present, the tetrazolium salt is reduced by cellular reductases. This reduction process converts the soluble, often colorless, tetrazolium salt into a water-insoluble, colored formazan product. The intensity of the color produced is directly proportional to the number of viable cells or the level of metabolic activity.

Commonly used tetrazolium salts include MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium), and WST-1 (4-[3-(4-Iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate). These reagents are valuable tools in research for cell proliferation studies, cytotoxicity assays, and drug screening. The tetrazoliumring is the core structural feature responsible for their redox properties.