Instability of the oxy form of sickle hemoglobin and of methemoglobin in isopropanol.

Oxygenated hemoglobin from water-lysed sickle erythrocytes preciptated more rapidly than hemoglobin from normal cells when exposed to 17% isopropanol in 0.1 M tris, pH 7.4, buffer (the isopropanol solubility test of Carrell and Kay). Precipitates became visible after approximately 20 minutes of incubation with SS, AS, or SC blood, while AC hemoglobin and normal adult A hemoglobin required 40-60 minutes of precipitate. Methemoglobin comprised less than 1.5% of the total hemoglobin present in all samples under study. Significant preciptation of methemoglobin did not occur unless methemoglobin levels were greater than 8%. Solubilization of the precipitate in 6M urea-barbital buffer and subsequent electrophoresis demonstrated that the insoluble material was sickle hemoglobin (Betas chain). The results of these experiments confirm previous findings indicating that even fully oxygenated sickle hemoglobin is unstable.