Complex Investigation of the Similarities and Differences between Ten Commercially Available Human Serum Albumin Preparations

Human serum albumin (HSA) maintains the oncotic pressure in the blood, also having buffer and antioxidant functions. Furthermore, numerous ligand molecules are circulating dominantly in albumin-bound form in the intravascular water space. The formation of stable ligand–albumin complexes commonly has significant physiological, pharmacological, and/or toxicological importance. Regarding ligand–HSA interactions, certain studies show controversial results that may have partly resulted from the differences between the protein preparations applied. To test this hypothesis, 10 HSA preparations were obtained, and then their albumin and free fatty acid content, fructosamine and free thiol levels, antioxidant capacity, fluorescence emission spectra, and ligand binding ability were examined. Our results demonstrate that sometimes even major differences can be observed when we compare these proteins. Therefore, the precise specification and the careful selection of HSA preparations seem to be reasonable.