Discovery of Mitochondria Functions
Many more individuals started to work with the organelle over the next few decades, each of whom discovered an important mitochondrial function within the cell.
In 1912, a German biochemist named Otto Heinrich Warburg hypothesized that an enzyme within cells enabled the processing of oxygen. He showed that cyanide had an effect on respiration at the cellular level. Further research was conducted by David Keilin in 1923 to show how the oxidation state within cytochromes (hemoproteins responsible for electron transport) was changed during respiration. He later identified the existence of cytochrome c, part of the inner membrane of mitochondria.
Adenosine triphosphate (ATP), the transporter of chemical energy within cells, was isolated in 1929 by C.H. Fiske and Y. Subbarow. Then, independent studies by H.M. Kalckar and V.A. Belitser showed how the addition of a phosphate to protein aids in cellular respiration in a process called oxidative phosphorylation.
Full discovery of mitochondria continued as the organelle was harvested from the liver, giving scientists greater access to its functions. Eugene Kennedy and Albert Lehninger showed how oxidation occurs within mitochondria in 1950, and by 1978, Nobel Prize-winner Peter D. Mitchell established his theory on chemiosmotics. He described the diffusion of hydrogen ions across membranes, and its relation to ATP during respiration in eukaryotic cells. This helped establish the overall purpose of mitochondria, to work as the organelle that converts the potential energy of food molecules into ATP.
Prof. Paul Boyer, who discovered the mitochondria's role in ATP synthase (or the combining of adenosine diphosphate and inorganic phosphate to create ATP) won a Nobel Prize in 1997.