Figure 3. Increase in DMSO content promotes spontaneous heme solubilization and crystallization in acidic conditions.

(A) Kinetics of spontaneous heme crystallization were performed at different concentrations of DMSO with heme at 100 µM over 24 h using 0.5 M sodium acetate buffer, pH 4.8 at 28°C with a final volume of 1.0 mL. Data are expressed as mean ± SEM, of least three different experiments. Open square: control; open triangle: 4.6% DMSO; inverted gray triangle: 8.3% DMSO; dark gray square: 15.1% DMSO; black circle 27.7% DMSO. (B) Correlation of spontaneous βH formation at 24 h with heme solubilization at different DMSO concentrations (r² = 0.8791).