Bulk properties of the lipid bilayer are not essential for the thermal stability of Na,K-ATPase from shark rectal gland or pig kidney

► The thermal stability of pig Na,K-ATPase is larger than that of shark Na,K-ATPase. ► Native pig lipids are less fluid than native shark lipids. ► Purification and reconstitution in native lipids did not affect thermal stability. ► 9-fold dilution with exogenous lipids did not alter the thermostabilities. ► The difference in stability is not mediated by bulk phospholipid properties.