Fig 5. The effect of storage at -20°C on α₂M chaperone activity.

(A) Images of native PAGE (3–8% Tris-acetate) analyses of α₂M stored in 20 mM phosphate buffer, pH 7.4 (4°C or -20°C, 1 month). The latter sample was rapidly frozen in LN prior to storage at -20°C. (B) Corresponding bisANS fluorescence measurements for the α₂M samples described in (A). The results shown are the values of the mean bisANS fluorescence (n = 3±SD) in AFU. * Denotes significantly increased bisANS fluorescence as a result of storage at -20°C (Student’s t-test p < 0.01) (C) Turbidity measurements of CPK aggregation in the presence or absence of α₂M which had been stored at 4°C or -20°C as described in (A). The data are from individual measurements and are representative of several different experiments.