STOCKHOLM — An American and two Japanese scientists won the 2010 Nobel Prize in chemistry today for developing chemical methods widely used to make potential cancer drugs and other medicines, as well as slimmed-down computer screens.

Richard Heck, Ei-ichi Negishi and Akira Suzuki were honored for their development four decades ago of one of the most sophisticated tools available to chemists called palladium-catalyzed cross couplings.

It lets chemists join carbon atoms together, a key step in the process of building complex molecules. Their methods are now used worldwide in commercial production of pharmaceuticals and molecules used to make electronics, the Royal Swedish Academy of Sciences said.

Heck, 79, is a professor emeritus at the University of Delaware, now living in the Philippines. Negishi, 75, is a chemistry professor at Purdue University in West Lafayette, Ind., and 80-year-old Suzuki is a retired professor from Hokkaido University in Sapporo, Japan.