F-ATPase delta（ATP5D) catalyzes ATP synthesis， employing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation. ATP synthase is composed of 2 linked multi-subunit complexes: F1-the soluble catalytic core and Fo- the membrane-spanning component， which comprise the proton channel. The catalytic portion of mitochondrial ATP synthase consists of five different subunits（alpha， beta， gamma， delta， and epsilon) assembled with a stoichiometry of 3 alphas， 3 betas， and a single representative of the other three. The proton channel consists of three main subunits-a， b， c. ATP5D is the delta subunit of the catalytic core.
