Hb Gun Hill has been found in an asymptomatic black female living in Alabama; neither her parents nor her two siblings carry the variant. The deletion of five mino acid residues in theβchain of lib Gun Hill (α2β291-95 deleted) causes this vartant to have a high oxygen affinity, an interaction coefficient of unity and an absence of the Bohr effect. The rate of oxidation of liganded Hb Gun Hill by the ferricyanide ion follovs first-order kinetics. Hb Gun Hill is to a great extent dissociated into dimers over a wide range of pH values.