 ATP was discovered in 1929 by Karl Lohmann , and independently by Cyrus Fiske and <unk> <unk> of Harvard Medical School , but its correct structure was not determined until some years later . It was proposed to be the intermediary molecule between energy @-@ yielding and energy @-@ requiring reactions in cells by Fritz Albert Lipmann in 1941 . It was first artificially synthesized by Alexander Todd in 1948 . 
