An unstable hemoglobin variant was found in a 24-year-old Chinese of Han origin. It had an electrophoretic mobility slightly faster than that of Hb A2, but could not be separated from it completely by cellulose acetate elec-trophoresis (pH 8.6). Chromatography on a DE-52 column showed that the variant amounted to approximately 13% of the total hemoglobin.Structural analysis showed that the hemoglobin had the structureα27(B8) Glu→Lys. It was named Hemoglobin Shuangfeng. Theα27 Glu residue is an invariable residue located near theα1βlcontact.