Hemoglobin Calais [beta 76 (E20) Ala----Pro]: a hemoglobin variant with decreased intrinsic oxygen affinity.
Hb Calais [beta 76 (E20) Ala----Pro] is a new human hemoglobin variant displaying a decreased oxygen affinity. The only electrophoretical difference with Hb A was a slightly more acidic isoelectric point. A 2-fold decrease in the oxygen affinity was found by equilibrium measurements performed in a suspension of intact red blood cells and in the lysate. It was confirmed by kinetic studies of the purified abnormal hemoglobin. The rate of methemoglobin formation at 37 degrees C of Hb Calais was also increased relative to Hb A. The mechanism by which the Pro for Ala substitution of an external residue in the beta-chains results in these profound functional abnormalities is unclear. Subtle changes at the heme pocket, at a distance from the mutation, may be a plausible explanation for the effects observed.
Wajcman
H
H
INSERM U299, Hôpital de Bicêtre, Le Kremlin Bicêtre, France.
Kister
J
J
Marden
M
M
Bohn
B
B
Blouquit
Y
Y
Descamps
J
J
Goudemand
M
M
Poyart
C
C
Galacteros
F
F
D000328:Adult; D000595:Amino Acid Sequence; D001665:Binding Sites; D005260:Female; D006455:Hemoglobins, Abnormal / Q000378:metabolism*; D006801:Humans; D007526:Isoelectric Point; D008706:Methemoglobin / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010100:Oxygen / Q000378:metabolism*; D011487:Protein Conformation; D011995:Recombination, Genetic
D006455:Hemoglobins, Abnormal; C066849:hemoglobin Calais; D008706:Methemoglobin; D010100:Oxygen