TY - JOUR
T1 - Cobalt-substituted hemoglobin Zürich (α2β263His→Arg). Oxygen equilibria and EPR spectra
AU - Ikeda-Saito, Masao
AU - Brunori, Maurizio
AU - Winterhalter, Kaspar H.
AU - Tonetani, Takashi
N1 - Funding Information:
The authors wish to thank Dr. M.F. Perutz for sending the structural data on FeHb Ziirich prior to publication. This work was supported by Research Grant HL 14508 from the National Heart, Lung and Blood Institute and Research Grant PCM 77-00811 from the National Science Foundation and was carried out under the auspices of NATO Science Program (998). M.B. was partially supported by the National Research Council (CNR) of Italy (Special Project of Biomedical Engineering-Chim 1).
PY - 1979/9/26
Y1 - 1979/9/26
N2 - Cobalt hemoglobin Zürich (α2β263His→Arg) has been successfully reconstituted from the apohemoglobin Zürich and cobaltous protoporphyrin IX. The oxygen affinity of cobalt hemoglobin Zurich, as well as that of iron hemoglobin Zürich, were measured in the absence and presence of organic phosphate and Cl-. The overall oxygen affinity of cobalt hemoglobin Zürich was found to be higher and the cooperativity as measured by the n value was smaller than those of cobalt hemoglobin A. Organic phosphate and Cl- affect the oxygen equilibrium properties of cobalt hemoglobin Zürich in a manner similar to that of cobalt hemoglobin A, but to a lesser extant than cobalt hemoglobin A. The EPR spectrum of oxy cobalt hemoglobin Zürich is less sensitive to the replacement of the buffer system from H2O to 2H2O, indicating that the hydrogen bond between the distal amino acid residue and the bound oxygen is not formed in the abnormal β subunits. The deoxy EPR spectrum of cobalt hemoglobin Zürich is similar to that of deoxy cobalt hemoglobin A, suggesting that the deoxy cobalt hemoglobin Zürich is predominantly in the deoxy quaternary structure (T state).
AB - Cobalt hemoglobin Zürich (α2β263His→Arg) has been successfully reconstituted from the apohemoglobin Zürich and cobaltous protoporphyrin IX. The oxygen affinity of cobalt hemoglobin Zurich, as well as that of iron hemoglobin Zürich, were measured in the absence and presence of organic phosphate and Cl-. The overall oxygen affinity of cobalt hemoglobin Zürich was found to be higher and the cooperativity as measured by the n value was smaller than those of cobalt hemoglobin A. Organic phosphate and Cl- affect the oxygen equilibrium properties of cobalt hemoglobin Zürich in a manner similar to that of cobalt hemoglobin A, but to a lesser extant than cobalt hemoglobin A. The EPR spectrum of oxy cobalt hemoglobin Zürich is less sensitive to the replacement of the buffer system from H2O to 2H2O, indicating that the hydrogen bond between the distal amino acid residue and the bound oxygen is not formed in the abnormal β subunits. The deoxy EPR spectrum of cobalt hemoglobin Zürich is similar to that of deoxy cobalt hemoglobin A, suggesting that the deoxy cobalt hemoglobin Zürich is predominantly in the deoxy quaternary structure (T state).
KW - (ESR)
KW - Cobalt hemoglobin
KW - Hemoglobin Zürich
KW - Oxygen affinity
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U2 - 10.1016/0005-2795(79)90200-9
DO - 10.1016/0005-2795(79)90200-9
M3 - Article
C2 - 232666
AN - SCOPUS:0018725341
VL - 580
SP - 91
EP - 99
JO - BBA - Protein Structure
JF - BBA - Protein Structure
SN - 1570-9639
IS - 1
ER -