Hemoglobin Dakar = Hb Grady: demonstration by a new approach to the analysis of the tryptic core region of the alpha chain and oxygen equilibrium properties

Hemoglobin Nouakchott [alpha 114(GH2)Pro----Leu]: a new hemoglobin variant displaying an unusual increase in hydrophobicity

The most striking fact in Hb Nouakchott [alpha 114(GH2)Pro----Leu] is the highly increased hydrophobicity of the abnormal chain. In comparison to other variants carrying the same amino-acid substitution, but at another position, the involvement of the environmental domains in the expression of the hydrophobicity is shown. Even though the substitution concerned a proline residue, it was without consequences on the oxygen binding and the stability of the molecule.

Structural study of hemoglobin Knossos, beta 27 (B9) Ala leads to Ser. A new abnormal hemoglobin present as a silent beta-thalassemia

A new electrophoretically silent hemoglobin variant is described that produces the classical phenotype of beta thalassemic intermedia in association with beta thalassemia trait. This variant has the expression of a silent beta thalassemia trait. The abnormal hemoglobin was detected by acid-urea-Triton-acrylamide electrophoresis and further demonstrated by isoelectric focusing. The amount of the variant in carrier is approximately 30% of the total hemoglobin. No instability was found. Absence of hemoglobin A in the propositus blood facilitated structural studies. Peptides maps were normal but analysis of individual peptide spots showed an Ala leads to Ser substitution in the beta T3. This variant has been previously called Hb Knossos (beta 27 (B9) Ala leads to Ser).

Mutant hemoglobins having elongated chains

Globin subunits may be elongated because of a base substitution in the termination codon, a crossover out of phase (frame shift) or a crossover in phase. This review presents structural, genetic, biosynthetic and clinical information on the eight variants having elongated chains which have been described to date.