Direct measurement of carbon monoxide bound to different subunits of hemoglobin A in solution and in red cells by infrared spectroscopy.
Infrared spectra for carbon monoxide bound to alpha and beta subunits of human hemoglobin A have subunit differences near 1950 cm-1 and indicate that 92% of the alpha subunits exist in one conformer and 5% in a second conformer under conditions where 99% of the beta subunit is in only one conformation. The sum of the separated subunit spectra is equivalent to the alpha 2 beta 2 tetramer spectrum. CO infrared spectra indicate that CO displaces O2 from HbO2 in red cells or in solution preferentially at the beta subunits. The measurement of C-O stretch bands provides a direct method for characterization of ligand binding sites within intact cells.
D002248:Carbon Monoxide / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D006441:Hemoglobin A / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
D046911:Macromolecular Substances; D002248:Carbon Monoxide; D006441:Hemoglobin A