HB Handa [a90 (FG 2) Lys à Met]: Structure and Biosynthesis of a new Slightly Higher Oxygen Affinity Variant

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Abstract
Hb Handa, an abnormal hemoglobin which isoelectrofocussed anodally to Hb A, was found in a 15-year-old Japanese girl and her mother, who were apparently healthy. Clinical and hematological examinations showed no abnormality in individual heterozygous for this mutant gene except for a slight increase of reticulocyte count (2.1–2.4%). Structural studies disclosed an a chain anomaly and substitution of α90 (FG 2) Lys à Met. The content of the abnormal hemoglobin in the hemolysate was 17.5–18.3% of the hemoglobin. The isopropanol precipitation test was negative. The purified abnormal hemoglobin showed a slightly higher oxygen affinity than that of Hb A, but Hill's n constant, Bohr effect and organic phosphate effect were within the normal range. Globin chain biosynthesis in reticulocytes indicated that the production rate of the abnormal a chain was suppressed to 38% of the normal level.