Thermal stability of recombinant Na,K-ATPase preparations made with SOPS, Soy PC, or SOPS plus Soy PC. Na,K-ATPases (α1β1FXYD1) was prepared in 0.05 mg/ml cholesterol, 0.3 mg/ml C12E8 and 0.17 mg/ml SOPS, 0.17 mg/ml Soy PC, or 0.07 mg/ml SOPS plus 0.1 mg/ml Soy PC. Complexes were incubated at 45 °C for the indicated times before activity measurement. vt/v0 represents activity at time t relative to activity v0 before inactivation.