Hemoglobin subunits

FIGURE 5-8 Dominant interactions between hemoglobin subunits. 

In addition to oxygen, hemoglobin subunits can also carry carbon dioxide. This is performed by covalent addition of C02 to the N termini of the hemoglobin chains to produce a carbonate structure. Propose reactions for this process utilizing (a) C02 and... 

Zahavy E, Willner I. Photoinduced electron transfer in eosin-modified Co(II)-protoporphyrin IX reconstituted myoglobin and a- or /3-hemoglobin subunits photocata-lytic transformations by the reconstituted photoenzymes. / Am Chem Soc 1996 118 12499-514. 

It has been estimated that it takes —lrnin to synthesize one hemoglobin subunit from its constituent amino acids. Using this fact, calculate how many hemoglobin molecules are produced on average at any one time in the differentiation of the cell. 

Arrangement of hemoglobin subunits. The four polypeptide subunits are located at the corners of a tetrahedron to give a roughly spherical structure. 

Mutations in Genes Encoding Hemoglobin Subunits Can Result in Disease... 

The structural changes in the hemoglobin subunits, accompanying the oxygenation of hemoglobin have been attributed to a 0.8-A shift of the iron atoms out of the porphyrin planes [Perutz (145)]. If this... 

BPG further accelerates the release of oxygen from hemoglobin. As soon as O2 is released from one of the four hemoglobin subunits, BPG begins to work its way back into the space in the hemoglobin molecule. This causes shape changes in the subimits that allow them to immediately release their boimd oxygen. 

M. Faraggi and M.H. Klapper, Intramolecular Long-Range Electron Transfer in the a-Hemoglobin Subunit, J. Am. Chem. Soc., 110 (1988) 5753. 

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