Mercuri-nitrophenol as a reporter group for the conformational change of hemoglobin.
One mole of horse hemoglobin tetramer reacts with 2 moles of 2-chloromercuri-4-nitrophenol (MNP) at beta 93 cysteine. The difference spectra between NMP-bound hemoglobin and hemoglobin, measured with the aid of ascorbic acid and ascorate oxidase [EC 1.10.3.3] as deoxygenation reagents, indicate that the pK of the phenolic hydroxyl group of MNP increases by 0.6 to 0.8 pH unit on deoxygenation of the hemoglobin. The Hill constant of the modified hemoglobin changes with pH. It decreases from about 2.4 at pH 6.8 to about 1.0 at pH 9.0 This effect of the reagent is interpreted as inherent to the reporter groups.
D000818:Animals; D001204:Ascorbate Oxidase; D001205:Ascorbic Acid; D055598:Chemical Phenomena; D002621:Chemistry; D006454:Hemoglobins / Q000032:analysis; D006736:Horses; D006863:Hydrogen-Ion Concentration; D008623:Mercaptoethanol / Q000032:analysis; D008628:Mercury / Q000032:analysis; D009596:Nitrophenols; D010100:Oxygen; D011487:Protein Conformation
D006454:Hemoglobins; D009596:Nitrophenols; D008623:Mercaptoethanol; D001204:Ascorbate Oxidase; D008628:Mercury; D001205:Ascorbic Acid; D010100:Oxygen