Molecular Stability and Function of Hemoglobins Hasharon (α₂ 47(CD5)ASP→HISβ₂) and Hasharon (α₂ 47 (CD5) ASP → HIS δ₂)

Abstract

The molecular stability and function of hemoglobin (Hb) Hasharon (α₂Hβ₂) and Hb Hasharon₂ (α₂ H δ₂) were studied and compared to Hbs A, A₂ and S. Hb Hasharon and Hb Hasharon had slightly lower P₅₀ values than Hb A and Hb A₂ but had normal responses to organic phosphates. The molecular stability of Hb Hasharon and Hb Hasharon (as measured by mechanical shaking and heat denaturation at 60° 6) were less than Hb A and Hb A₂ but greater than Hb S in the oxy- and carbonmonoxy-forms. In the met-form, however, Hb Hasharon and Hb Hasharon₂ were less stable than hemoglobins S, A and A₂. The oxy-form of Hb Hasharon forms methemoglobin at a faster rate than Hb A and Hb S. The mechanical and heat stabilities and the rate formation of oxy-Hb Hasharon were studied in the presence of sulfisoxazole. This drug increased the rate of methemoglobin formation, thus causing a further decrease in the stability of Hb Hasharon. The relationship between these laboratory findings and previously observed clinical findings associated with Hb Hasharon are discussed.