| Citation | Distinguished for his work on biological membrane structure.
In earlier work on the biochemistry of protein synthesis, Bretscher made distinctive contributions to the mechanisms of polypeptide chain initiation and termination. In particular he showed that the latter was an active process and not simply the consequence of stopping protein synthesis. But his most important work has been on the structure of biological membranes. Using chemical labelling methods, which he developed, he was the first to demonstrate the existence of oriented transmembrane proteins. He showed that the major sialoglycoprotein of the red cell spans the bilayer with its C-terminal region on the inside. With the same reagent he discovered that the bilayer structure is itself asymmetrical with most, if not all, of the phosphatidyl-ethanolamine in the inner leaflet. On the basis of this research he proposed new principles of biological membrane structure which are now widely accepted. |