ATPases (or ATP synthases) are membrane-bound enzyme complexes that combine ATP synthesis with the transport of protons across a membrane. They thereby harness energy from a proton gradient and produce ATP. The function of ATPase can be utilized as an indicator of general health and functioning in studies, as in the case of virus infected phytoplankton in a recent publication. The study utilized an antibody against the beta subunit of ATP synthase
in plants and micro-organisms.