NCIt definition : A tetrameric complex of 2 molecules of hemoglobin subunit alpha (encoded by either
the HBA1 or HBA2 gene) and 2 molecules of a hemoglobin subunit beta variant where
the glutamic acid residue at position 7 has been replaced by lysine.;
NCIt note : This hemoglobin subunit beta variant is often reported in the literature as Glu6Lys
(E6K) but that numbering does not include the initiator methionine, which is post-translationally
removed during hemoglobin synthesis.;