FIGURE 3.

(A) Effect of freezing on the ANS fluorescence intensity (λ_max = 465 nm) profile of 2 μM BSA (2 mM Hepes, pH 7.5, plus 25 mM NaCl); comparison between supercooled solution (▪) and ice (•) at −5°C. Intensities in ice were corrected (increased by 20%) for the lower transmittance of the frozen state. (B) Effect of temperature on the enhancement of ANS fluorescence in ice by BSA (2 μM). The [ANS]_{(water pool)} is derived by multiplying the ANS concentration in solution by the corresponding freeze concentration factors: 55 (−5°C) and 120 (−13°C).