Functional properties of rat hemoglobin fractions
Starodub, N.F.; Kriklivyĭ, I.A.; Artiukh, V.P.; Rekun, G.M.
Biokhimiia 45(5): 812-820
1980
ISSN/ISBN: 0320-9725 PMID: 6769507 Document Number: 161125
The functional properties of total hemoglobin and some of its major fractions obtained by polyacrylamide gel disk-electrophoresis were studied. It was shown that p50 for intact hemoglobin is 1.18, that for fractions 2, 4-6-1.37-1.65 mm Hg. The affinity of fraction 3 for oxygen is significantly higher. In the presence of CO2 (40 mm Hg) p50 is much higher for fractions 4 and 6 as compared with fractions 3 and 5. Fraction 3 reveals the highest resistance to autooxidation; fractions 2 and 5 possess the highest sensitivity. ATP and pyridoxal-5'-phosphate stimulate the autooxidation and decrease the affinity for hemoglobin oxygen of fractions 3 and 4 in a greater degree than of the other fractions (for fraction 3 more than for fraction 4). A similar dependence is observed in case of fractions 5 and 6. The effective constant (ki) of dissociation of heme- and globin bonds for HbCO for fraction 3 is 2.38.10(-3) s-1. For the other fractions this value is considerably lower. The ki value for all fractions is increased with a transition from the carboxy- to methehemoglobin. The level of individual components of the heterogenous system of hemoglobin in the blood of embryos, adult intact rats and in anemic and hypoxic animals is given. The interrelationship of functional and structural properties of the hemoglobin fractions and their role in oxygen supply of tissues under the above-described conditions are discussed.