Glutathione, A tripeptide that serves as an electron donor in cells
Glutathione, A tripeptide that serves as an electron donor in cells
Glutathione (GSH) is an important antioxidant in plants, animals, fungi and some bacteria and archaea, preventing damage to important cellular components caused by reactive oxygen species such as free radicals and peroxides. It is a tripeptide with a gamma peptide linkage between the carboxyl group of the glutamate side-chain and the amine group of cysteine (which is attached by normal peptide linkage to a glycine).
Thiol groups are reducing agents,…
Seaborgium
Seaborgium is a synthetic element with the symbol Sg and atomic number 106, whose most stable isotope 271Sg has a half-life of 1.9 minutes. A more recently discovered isotope 269Sg has a potentially slightly longer half-life (ca. 2.1 min) based on the observation of a single decay. Chemistry experiments with seaborgium have firmly placed it in group 6 as a heavier homologue to tungsten.
Discovery Scientists working at the Joint Institute for Nuclear Research in Dubna, USSR reported their discovery of…
Specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density (mass of the same unit volume) of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for liquids or air for gases. Temperature and pressure must be specified for both the sample and the reference. Pressure is…