Thermo-stability of MelBSt extracted by DDM or an RGA (RGA-C8, RGA-C9, RGA-C10, RGA-C11, RGA-C12 or RGA-C13). (a) Western blot analysis. Membranes containing MelBSt mixed with the indicated detergent were incubated at 0°C or an elevated temperature (45, 55 or 65°C) and subjected to ultracentrifugation. The amounts of the transporter in the solutions were analysed by SDS-15% PAGE and Western blotting. The band from the untreated membrane sample (Memb) represents the total amount of the transporter present in the membranes before detergent treatment. (b) Histogram. The amount of soluble protein in a detergent detected in panel (a) was expressed as a percentage of the total amount of the transporter in the untreated membrane sample. Error bars, SEM, n = 3.