Biotins, Streptavidins (253)

Biotin, previously referred to as coenzyme R and vitamin H, is a water-soluble compound, meaning it is not stored in the body. It plays a critical role in various bodily functions and is essential for the activity of specific enzymes known as carboxylases. These biotin-dependent enzymes are crucial for key metabolic processes, including the synthesis of glucose and fatty acids. Streptavidin, a 52.8 kDa protein derived from Streptomyces avidinii, forms homotetramers that exhibit an exceptionally high affinity for biotin. The interaction between biotin and streptavidin is among the strongest non-covalent bonds in nature, with a dissociation constant of roughly 1 μmol/L. Owing to the remarkable stability of the streptavidin-biotin complex against organic solvents, denaturants, detergents, proteolytic enzymes, and extreme conditions of temperature and pH, streptavidin is extensively utilized in molecular biology and bionanotechnology.