DOI:
Authors:
Haruo Homareda, Yoshine Nagano, Hideo Matsui
Abstract:
A polyclonal antibody against the Na + ,K + ‐ATPase holoenzyme was prepared. This antibody recognized native Na + ,K + ‐ATPase and inhibited its activity. The peptide fragments corresponding to various regions of the Na + ,K + ‐ATPase α‐subunit, which were synthesized from the cDNA, were immunoprecipitated with the antibody, and the M32‐D75, M158‐D197 and M470‐V552 fragments (the latter included K508, a putative ATP binding site) were identified as the epitopes. The M267‐I442 fragment, which included a phosphorylation site at D376, and the C‐terminal one‐third of the α‐subunit from M615 to the C‐terminus, were not detected using this antibody. These results suggest that at least three regions on the Na + ,K + ‐ATPase α‐subunit, M32‐D75, M158‐D197 and M470‐V552, cover its exposed regions, and that some of them are essential for ATPase activity.