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Peter D. Mitchell proposed the chemiosmotic hypothesis in 1961. [1] In brief, the hypothesis was that most adenosine triphosphate (ATP) synthesis in respiring cells comes from the electrochemical gradient across the inner membranes of mitochondria by using the energy of NADH and FADH 2 formed during the oxidative breakdown of energy-rich molecules such as glucose.
Mitchell's chemiosmotic hypothesis was the basis for understanding the actual process of oxidative phosphorylation. At the time, the biochemical mechanism of ATP synthesis by oxidative phosphorylation was unknown. In chemiosmosis, ions move down their electrochemical gradient across a membrane.
This ATP synthesis reaction is called the binding change mechanism and involves the active site of a β subunit cycling between three states. [77] In the "open" state, ADP and phosphate enter the active site (shown in brown in the diagram). The protein then closes up around the molecules and binds them loosely – the "loose" state (shown in red).
Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP synthesis through oxidative phosphorylation. In the 1960s through the 1970s, Paul Boyer , a UCLA Professor, developed the binding change, or flip-flop, mechanism theory, which postulated that ATP synthesis is dependent on a conformational change in ATP synthase ...
Including one H + for the transport reactions, this means that synthesis of one ATP requires 1 + 10/3 = 4.33 protons in yeast and 1 + 8/3 = 3.67 in vertebrates. This would imply that in human mitochondria the 10 protons from oxidizing NADH would produce 2.72 ATP (instead of 2.5) and the 6 protons from oxidizing succinate or ubiquinol would ...
Jennifer Moyle (April 30, 1921 - August 1, 2016) [1] [2] was a British biochemist who helped discover the chemiosmotic mechanism of ATP synthesis. Jennifer Moyle at Cambridge, ca 1950. She also conducted research on the properties of purified isocitric enzymes [3] and calcium import in the mitochondria during cellular respiration. [4]
In biology, electrochemical gradients allow cells to control the direction ions move across membranes. In mitochondria and chloroplasts, proton gradients generate a chemiosmotic potential used to synthesize ATP, [1] and the sodium-potassium gradient helps neural synapses quickly transmit information. [citation needed]
André Tridon Jagendorf (October 21, 1926 – March 13, 2017) was an American Liberty Hyde Bailey Professor Emeritus in the Section of Plant Biology [1] [2] [3] at Cornell University who is notable for providing direct evidence that chloroplasts synthesize adenosine triphosphate (ATP) using the chemiosmotic mechanism proposed by Peter Mitchell.