Svedberg — Discoverer of the protein macromolecules

The(odor) Svedberg* (1884‐1971), Uppsala University, was the first professor of physical chemistry in Sweden. He started his research in 1904 as a colloid chemist. He prepared inorganic dispersions by electrical discharge through organic liquids, measured particle size and size distribution of colloids by diffusion and sedimentation rates and invented the ultracentrifuge for convection‐free sedimentation of colloidal particles. In 1924 Svedberg applied the ultracentrifuge for studies of haemoglobin in aqueous solution. Unexpectedly he found that the protein was not a gel of associated small molecules. It sedimented as macromolecules of uniform mass (68 000 dalton), i.e. is monodisperse. In subsequent work Svedberg found that other proteins like ovalbumin (from egg white) and haemocyanins from snails and other invertebrates also are monodisperse or contain a few uniform macromolecular components. After extensive studies of soluble protein molecules from a large number of animals and plants, Svedberg classified the species and could trace the relations for the species from the molecular mass of their protein macromolecules. Studies of soluble polysaccharides from bulbs also showed well defined macromolecules of masses that could be related to the various botanical species. Other native substances like cellulose, other wood polysaccharides and starch were found to be of high molecular mass but polydisperse. Svedberg's research in the 1920's and 1930's gave strong experimental support for Staudinger's macromolecular concept although Svedberg, at the time of his own important discoveries, was not influenced by Staudinger. Svedberg's discovery of the protein macromolecules and their uniform molecular mass initiated the macromolecular research in biochemistry.