Covalent binding of negatively charged phospholipid to Na,K-ATPase

Phosphatidylglycolaldehyde and its lyso derivative were applied as probes in order to study lipid-protein interactions with purified, membrane-bound Na,K-ATPase. Reduction with [3H]NaCNBH3 led to formation of a stable chemical derivative between added lipid and protein. The extent of modification of the two subunits of Na,K-ATPase was similar. Extensive tryptic digestion of derivatized ATPase resulted in cleavage of the alpha-subunit without hydrolysis of the beta-subunit.