Figure 5.

The effect of free heme on the metastable dense liquid clusters in deoxy-HbS solutions. Volume fraction, ϕ₂, occupied by clusters was determined as in Pan et al. (45) at the five HbS concentrations shown in the legend, and in the presence of heme at one of these concentrations. The temperature was 22°C. (a) Time dependence of the volume fraction at five solution compositions, as indicated in the plot. (b) Dependence of the average volume fraction from a on HbS concentration. The solid square at 121 mg ml⁻¹ indicates the volume fraction in the presence of 66 μM of free heme; open symbols indicate volume fraction in the absence of heme. The line is a guide for the eye.