Na/K-ATPase is a membrane-associated enzyme responsible for the active transport of Na + and K+, and the maintenance of Na+ and K+ gradients across membrane. It is a heterodimer of two different kinds subunit, a large alpha subunit and a smaller glycoprotein subunit beta. At least four distinct alpha subunits and four beta subunit isoforms have been identified. In some tissues, it has been showed that Na/K-ATPase is associated with third subunit gamma, a small regulatory protein. CD298 (also known as Na/K-ATPase beta3) is a 42-kDa glycoprotein and one of beta subunit isoforms. CD298 has been detected in amphibians, mouse, rat,and human. In rat, CD298 expresses in a variety of tissues including testis, brain, kidney, spleen, stomach, small intestine, colon, lung, and liver. In theretina Na/K-ATPase restores Na+ and K+ gradients used by photoreceptor dark current, synaptic activity, action potential, and CD298 is largely restricted to photoreceptors in the mouse and rat. In human, CD298 also involves in regulation of T and B lymphocyte proliferation.This antibody is specific to human CD298 and will be useful for FCM, immunoprecipitation, immunohistochemistry.