The overall reaction sequence is: ADP + Pi → ATP, where ADP and Pi are joined together by ATPsynthase
Energy is often released in the form of protium, or H+, moving down an electrochemical gradient, such as from the lumen into the stroma of chloroplasts or from the inter-membrane space into the matrix in mitochondria.
Located within the mitochondria, ATP synthase consists of 2 regions the FO portion is within the membrane.
The F1 portion of the ATP synthase is above the membrane, inside the matrix of the mitochondria.
Mitochondria structure: (1) inner membrane, (2) outer membrane, (3) cristae, (4) matrix
The nomenclature of the enzyme suffers from a long history. The F1 fraction derives its name from the term "Fraction 1" and FO (written as a subscript letter "o", not "zero") derives its name from being the oligomycin binding fraction. Oligomycin, an antibiotic, is able to inhibit the FO unit of ATP synthase.
These functional regions consist of different protein subunits.
The F1 particle is large and can be seen in the transmission electron microscope by negative staining. These are particles of 9 nm diameter that pepper the inner mitochondrial membrane. They were originally called elementary particles and were thought to contain the entire respiratory apparatus of the mitochondrion, but, through a long series of experiments, Ephraim Racker and his colleagues (who first isolated the F1 particle in 1961) were able to show that this particle is correlated with ATPase activity in uncoupled mitochondria and with the ATPase activity in submitochondrial particles created by exposing mitochondria to...