[Human serum albumin: news about an old acquaintance].

Human serum albumin is an important depot protein and transport protein for numerous endogenous and exogenous compounds. The ligands are mainly positively charged inorganic ions or negatively charged or electronegative organic molecules. Binding a non-binding compound to albumin can be achieved by coupling the compound to a ligand, such as a fatty acid. The protein can be used for extracorporeal detoxification. In particular, studies with albumin mutants and crystallographic studies of albumin-ligand complexes have given much new information about the location and structure of binding sites and about potential ligand interactions. Albumin also seems to be the quantitatively most important circulating antioxidant. Finally, this multifunctional protein has enzymatic properties which are so pronounced that they most probably can be used to convert prodrugs to active therapeutics.