Organic: Biochemical mechanisms and regulation of vitamins and vitamin-like cofactors

The vitamins are a group of organic compounds essential to cellular functions that range from immunity to all aspects of growth and metabolism. Currently, thirteen vitamins are considered nutritionally essential, i.e., inadequacies in function occur if an external source is not provided. Vitamins serve as cofactors or co-enzymatic catalysts, cell-signaling molecules, co-substrates, and antioxidants. Highlighted are the chemical properties of vitamins unique to specific functions. The focus is primarily on mechanisms of action and structural features that determine why a particular vitamin is suited for a biologically essential reaction or process. In addition, features for selected vitamin-like compounds are also described.