ATP synthase consists of a F and F subunit. The F subunit contains alpha and beta subunits of its own which can assist in the formation of ATP, or hydrolyze it to serve as a proton pump. Though most catalytic actions happen on the beta subunits, the alpha subunits each contain an arginine finger. The role of the arginine finger in ATP synthase is akin to the function of the arginine finger residues of G proteins; to help split ATP. For example, if the arginine of the arginine finger is substituted by lysine, possibly due to a missense mutation, the αR364K mutant results. In the αR364K mutant, the ability of ATP synthase to hydrolyze ATP is decreased around a thousandfold compared to the wild type.