War·burg \ˈvär-ˌbu̇rk\ Otto Heinrich (1883–1970), German biochemist. Warburg is considered by some the most accomplished biochemist of all time. He received doctorates in both medicine and chemistry. After World War I he began investigating the process by which oxygen is consumed in the cells of living organisms. He introduced the use of manometry as a means of studying the rates at which slices of living tissue take up oxygen. His research led to the identification of the role of the cytochromes. In 1931 Warburg was awarded the Nobel Prize for Physiology or Medicine for his research on respiratory enzymes. He also investigated photosynthesis and was the first to observe that the growth of malignant cells requires markedly smaller amounts of oxygen than that of normal cells.