Studies on modified hemoglobins
A semihemoglobin containing prosthetic groups only in the β-subunits (two hemes per tetramer) has been prepared by mixing together apo- α-subunits and native, heme-containing β-subunits. The semihemoglobin is found to be tetrameric and has optical properties similar to those of hemoglobin A. The oxy...
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| Published in | Archives of biochemistry and biophysics Vol. 145; no. 2; pp. 448 - 455 |
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| Main Authors | , , |
| Format | Journal Article |
| Language | English |
| Published |
Elsevier Inc
01.08.1971
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| Online Access | Get full text |
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| Summary: | A semihemoglobin containing prosthetic groups only in the
β-subunits (two hemes per tetramer) has been prepared by mixing together apo-
α-subunits and native, heme-containing
β-subunits. The semihemoglobin is found to be tetrameric and has optical properties similar to those of hemoglobin A. The oxygen affinity of the semihemoglobin is lower than that of isolated (Fe
+2)-subunits but not nearly so low as that of hemoglobin A, and the Hill coefficient for the semihemoglobin is near one. Addition of heme to the semihemoglobin (two hemes per tetramer) substantially lowers its oxygen affinity and partially restores cooperative oxygen binding.
The semihemoglobin demonstrates the requirement for a prosthetic group to be present in each hemoglobin subunit in order for the low oxygen-affinity configuration of hemoglobin to be present. Also, it lends further support to the nonequivalence of the subunits in the hemoglobin tetramer. |
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| ISSN: | 0003-9861 1096-0384 |
| DOI: | 10.1016/S0003-9861(71)80004-8 |