Hemoglobin binding

Hemoglobins bind four molecules of Oj per tetramer, one per heme. A molecule of Oj binds to a hemoglobin tetramer more readily if other Oj molecules are already bound (Figure 6-4). Termed cooperative binding, this phenomenon permits hemoglobin to maximize both the quantity of O2 loaded at the PO2 of the lungs and the quantity of O2 released at the PO2 of the peripheral tissues. Gooperative interactions, an exclusive property of multimeric proteins, are critically important to aerobic life. 

Fetal hemoglobin binds oxygen more tightly than HbA, and it has a decreased propensity to sickling. HbA2 also possesses this characteristic but to a lesser extent. RBCs that contain HbF sickle less readily than cells without. ISCs are found to have low HbF concentrations. In some patients, higher HbF may ameliorate the disease. 

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N6. Nyman, M., On plasma proteins with heme or hemoglobin binding capacity. Scand. J. Clin, ir Lab. Invest. 12, 121 (1960). 

Tl. Tombs, M. P., Hemoglobin-binding -globulin in human serum. Nature 186, 1055 (1960). 

Bimer G, Albrecht W, Neumann H-G. 1990. Biomonitoring of aromatic amines III. Hemoglobin binding of benzidine and some benzidine congeners. Arch Toxicol 64(2) 97-102. 

Mehanna, A.S. Abraham, D.J. Comparison of crystal and solution hemoglobin binding of selected antigelling agents and allosteric modifiers. Biochemistry 1990, 29, 3944-3952. 

Hemoglobin binds Oj at the high PO2 (100 mm Hg) of the lung capillary beds and transports it to the peripheral tissues, where Poj is lower (-30 mm Hg) and O2 dissociates from hemoglobin. 

Bimer, G Neumatm, H.-G (1988) Biomonitoring of aromatic amines. II Hemoglobin binding of some monocyclic aromatic amines. Arch. Toxicol., 62, 110-115 Bollag, J.-M., Blattmann, P. Laanio, T. (1978) Adsorption and transformation of four substituted anilines in soil. J. Am. Food Chem., 26, 1302-1306 Bull, D.L. (1973) Metabolism of chlordimefon in cotton plants. Environ. EntomoL, 2, 869-871 Chemical Information Services (1999) Directory of World Chemical Producers (Version 99.1.0) [CD-ROM], Dallas, TX... 

Hemoglobin binds oxygen with increasing affinity. 

Figure 7.17 Gel electrophoresis of haptoglobins. Haptoglobin 1-1 moves as a single component, whereas the other two types show genetically derived polymorphisms. Hemoglobin-binding activity is identical in the three types.

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