Description_x000D_ Application_x000D_ Vitamin B12 has been used:_x000D_ • as a constituent in vitamin mix solution in in vitro gut simulator_x000D_ • as a standard in size exclusion inductively coupled plasma mass spectroscopy (SEC-ICP-MS)_x000D_ • as a constituent of simulated plasma protein mixture for Raman spectra analysis_x000D_ • in surface plasmon resonance (SPR) analysis_x000D_ • as a medium supplement in neonatal rat ventricular myocytes (NRVM)_x000D_ Packaging_x000D_ 1, 5, 25 g in glass bottle_x000D_ 100, 250, 500 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ Vitamin B12 (cobalamin) refers to a group of chemically-related cobalt containing molecules involved in cell processes such as DNA synthesis, fatty acid synthesis, energy production and regulation. The physiologically active forms of vitamin B12 include methylcobalamin and adenosylcobalamin, whereas hydroxocobalamin (vitamin B12a, OHCbl) and cyanocobalamin (CNCbl) are storage and delivery forms. Bacteria-derived hydroxocobalamin (OHCbl) and CNCbl are converted in humans to useful coenzyme forms to support metabolic processes such as mitochondrial methylmalonylcoenzyme A mutase conversion of methylmalonic acid (MMA) to succinate to link lipid and carbohydrate metabolism, and activation of methionine synthase, the rate limiting step in the synthesis of methionine.