the maj ority of eukaryotes and prokaryotes. The synthesis of ATP occurs at a rate of

about 100 s- which maintains a concentration of about 3 mM ATP in Escherichia coli

and greater concentrations in mitochondria and chloroplasts with no noticeable product

inhibition (3). In eukaryotes, they are located in the inner mitochondrial membrane, or in

the thylakoid membrane of chloroplasts. In most bacteria, F1Fo ATP synthase is located

in the cytoplasmic membrane. Enzymes in this family utilize the electrochemical

gradient of protons across these membranes in order to synthesize ATP from ADP and

inorganic phosphate (Pi) in a coupled reaction. In bacteria, the reaction of ATP synthases

can be reversed if the situation of a dissipated electrochemical proton gradient arises. In

this case, ATP derived from glycolysis can be hydrolyzed in order to pump protons

across the membrane, creating a membrane potential. The membrane potential can then

be utilized to drive other cellular processes such as the extrusion of sodium ions, nutrient

uptake and flagellar rotation.

 An explosion of research concerning F1Fo ATP synthase has occurred during the

past few decades. In particular, a great deal of knowledge of the enzyme has been solved

only in the past decade. A plethora of relatively recent reviews concerning every aspect

of F1Fo ATP synthase can be found in the special editions of Journal ofBioenergetics

and Biomembranes (volume 32, 2000) and Biochimica et Biophysica Acta (volume 1458,

2000) as well as reviews authored by Noji and Yoshida (2001), Senior et al. (2002),

Capaldi et al. (2002) and Weber and Senior (2004). This chapter will provide detailed

explanations of what is currently known about F1Fo ATP synthase including the

mechanism of the enzyme as a whole as well as structure and functions of individual

subunits, equivalence of the bacterial enzyme to its eukaryotic equivalents and genetic