Studies on the function of abnormal hemoglobins II. Oxygen equilibrium of abnormal hemoglobins: Shimonoseki, Ube II, Hikari, Gifu, and Agenogi

Abstract

Oxygen equilibrium functions of abnormal hemoglobins discovered from Japanese families were studied. Hb Shimonoseki (E3α, Gln → Arg), Hb Ube II (E17α, Asn → Asp), Hb Hikari (E5β, Lys → Asn) and Hb Gifu (EF4β, Asn → Lys) have the same function as that of Hb A. These results further confirm the widely known fact that external residues generally do not have a very important role in the function of hemoglobin. Hb Agenogi (F6β, Glu → Lys), however, has a different function from that of Hb A:it has a slightly but obviously lower oxygen affinity than that of Hb A while the shape of the curve of the Bohr effect and the heme heme interaction are normal. A plausible mechanism for the lower oxygen affinity is proposed from the viewpoint of altered surroundings of oxygen-linked acid groups which are brought about by an interaction between the groups and the newly introduced residue, lysine.