Gelation kinetics of dilute hemoglobin from sickle cell anemia patients

Non-ideal behavior of sickle cell hemoglobin (Hb S) and varying experimental conditions have made gelling kinetic studies difficult. A new gelation kinetic procedure is developed in this study. This technique uses low Hb S concentrations (20-fold less than in conventional methods) without the need for a temperature jump. Gelation progress, monitored with a newly developed turbidimetric procedure at 815 nm, was fitted to a mono-exponential and a sigmoid-Emax models. These models allowed precise definitions of gelation delay periods, rate of rapid Hb S gelation and a parameter, T 1/2 which combines information from the delay and rapid gelation stages. All these parameters vary linearly with Hb S concentration. The merits of using T 1/2 are discussed.