|MadSci Network: Biochemistry|
Hi there! I assume you are talking about the ATP synthase enzyme found on the inner membrane of mitochondria. This enzyme constitutes about 15% of total inner membrane protein. It is a highly conserved molecule. This means not only is it similar between plants and animals but it is even very similar between mitochondria and chloroplasts. This protein is very old in evolutionary terms as well because it is also found in bacteria. To answer your other question, it is not known with any certainty how many H+ ions are needed to make each molecule of ATP. A standard assumption based on energy calculations suggests that 3 H+ must be driven through the membrane to synthesize one ATP molecule. Of course, depending on the energy status of the cell, the process can reverse itself and pump protons out of the inner membrane resulting in production of ADP from ATP.
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