Immunoaffinity isolation of Na,K-ATPase α3 isoform from pig kidney

AbstractThe Na,K-ATPase α3 isoform of the catalytic subunit has been isolated from pig kidney microsomes. The procedure employs immunoaffinity chromatography on Sepharose 4B covalently coupled with monospecific antibodies a-II against the synthetic peptide including the putative α3 N-terminus. The structural analysis provides unambiguous proof that the isolated protein corresponds to the third transcript for the α3 isoform. The N-terminal amino acid sequence determined, Met-Gly-Asp-Lys-Lys-Asp-Asp, shows that unlike the α1 and α2 proteins, the mature Na,K-ATPase α3 isoform lacks post-translational proteolytic processing.ATPase isozyme, (Na+ + K+)-; Immunoaffinity chromatography; N-terminal sequence analysi