Two Americans share Nobel chemistry award STOCKHOLM, Sweden, Oct. 10 (UPI) -- Two U.S. scientists received the 2012 Nobel Prize for Chemistry for their studies of G-protein-coupled receptors, the Royal Swedish Academy of Sciences said. Robert Lefkowitz and Brian Kobilka were awarded the prize for their work on an important family of receptors that allow cells to sense their environment to adapt to new situations, the academy said Wednesday in a release. Lefkowitz began using radioactivity in 1968 to trace cells' receptors, attaching an iodine isotope to hormones, and discovering several receptors, including a receptor for adrenalin, the academy said. The team achieved its next big step during the 1980s, when Kobilka isolated the gene that codes for the adrenalin receptor from the human genome, the academy said. When researchers analyzed the gene, they found the receptor was similar to one in the eye that captures light and realized a whole family of receptors, the G-protein-coupled receptors, looked and functioned in the same manner. About half of all medications achieve their effects through G-protein-coupled receptors. The studies by Lefkowitz and Kobilka are critical for understanding how G-protein-coupled receptors function, the academy said. In 2011, Kobilka achieved another breakthrough when he and his research team captured an image of an adrenalin receptor at the moment it is activated by a hormone and sends a signal into the cell. Bassam Z. Shakhashiri, president of the American Chemical Society, congratulated the laureates on behalf of the society's 640,000-plus members. They have made tremendous strides in our understanding of health and disease. Almost half of all prescription medications work through the mechanisms that Lefkowitz and Kobilka have explored," Shakhashiri said. The resulting insights are helping us develop new medicines for combating disease, one of the great global challenges facing humanity. Lefkowitz, born in 1943 in New York, is an investigator with the Howard Hughes Medical Institute, and a James B. Duke professor of medicine and professor of biochemistry at Duke University Medical Center, Durham, N.C. Kobilka, born in 1955 in Little Falls, Minn., is a professor of medicine and a professor of molecular and cellular physiology at Stanford University School of Medicine, Stanford, Calif.