Hemoglobin with acids

The amino acid sequence in hemoglobin, with 574 units, is known. 

Hemoglobinopathies have traditionally been defined as a family of dis orders caused by production of a structurally abnormal hemoglobin molecule, synthesis of insufficient quantities of normal hemoglobin, or, rarely, both. Sickle-cell anemia (HbS), hemoglobin C disease (HbC), and the thalassemia syndromes are representative hemoglobinopathies that can have severe clinical consequences. The first two conditions result from production of hemoglobin with an altered amino acid sequence, whereas the thalassemias are caused by decreased produc tion of normal hemoglobin. 

Figure 1. Optimum pH of pepsin partially purified from the stomach lining of arctic cod 30°C ( ) 5°C (A) A 280 = absorbancy of TCA solubles at 280 nm. Pepsin was assayed with acid-denatured hemoglobin (2%) at the indicated temperatures and activity was monitored by measurements of TCA-solu-ble products (53).

B48. Bonaventura, J., and Riggs, A., Hemoglobin Kansas, a human hemoglobin with a neutral amino acid substitution and an abnormal oxygen equilibrium. J. Biol. Chem. 243, 980-991 (1968). 

Table 2. Effects of royal jelly on die weight and hemoglobin content of the gels 5 days after implantation into mice of Matrigel supplemented with acidic fibroblast growth factor (aFGF) and heparin...

Electrophoresis at pH 6.4 using a citrate buffer is performed when an abnormal band is noted on alkaline Hb electrophoresis. Agarose is the preferred medium, with Acid Violet the preferred stain. Figure 31-10 shows the same Hb variants performed on agarose electrophoresis at pH 6.4 and stained with Acid Violet. The order of migration (cathode to anode, fastest to slowest) is Hb F, Hb A, Hb S, and Hb C. Hemoglobins D, G, I, J, O, A2, and E co-migrate with Hb A. 

Derivation By heating hemoglobin with acetic acid and sodium chloride. 

Reactive xenobiotic Intermediates may be covalently bound to amino acids, free or In proteins. For example the reactivity of epoxides have been studied In relation to formation of covalent bound products with the hemoglobin amino acids histidine, valine and to some extent also cysteine In dose monitor experiments (249,250). The hemoglobin must be hydrolyzed prior to analysis of histidine adducts while that Is not neccessary In order to characterize adducts to the N-termlnal valine (251). A few reference cysteine, histidine and valine xenobiotic adducts have been synthesized (250,252-254). The primary amino group of histidine Is occupied In the peptide bond, therefore this group must be protected In order, to favor tjeactlon at the other nucleo-... 

It is apparent from the above discussion that many hemoglobins with different amino acid substitutions demonstrate identical electrophoretic mobilities. Methods that rely on differences other than net charge are needed to establish the identity of these hemoglobins. Definitive... 

The pocket is large enough to accommodate ligands such as imidazoles (though these appear to be somewhat different complexes from those seen with myoglobin and hemoglobin), nicotinic acid (pyridine-... 

Only a small amount of absorbed MBOCA is excreted in urine as MBOCA in animals, and probably in humans as well (see Section 2.3). The methods used to detect MBOCA in urine are somewhat limited since they commonly measure unmetabolized MBOCA-not its metabolic by-products. Some methods have been developed to directly measure major MBOCA metabolites in urine. Other analytical methods pretreat urine samples with acid, base and/or heat to release MBOCA from its various conjugates. Another approach is to analyze the longer-lived complexes, such as MBOCA-hemoglobin adducts. The specific methods used are noted in the following text and in Table 6-1. 

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