The measurement of the intrinsic alkaline Bohr effect of various human haemoglobins by isoelectric focusing

Abstract

We have used isoelectric focusing to measure the differences between the pl values of various normal and mutant human haemoglobins when completely deoxygenated and when fully liganded with CO. It was assumed that the Apl(deox. -ox.) values might correspond quantitatively to the intrinsic alkaline Bohr effect, as most of the anionic cofactors of the haemoglobin molecule are 'stripped' off during the electrophoretic process. In haemoglobins known to exhibit a normal Bohr coefficient (AlogP50/ApH) in solutions, the ApI (deox. -ox.) [(1980), J. Mol. Biol. 138, 649-6701 for the mechanism of the alkaline Bohr effect, and also indicate that the transition between the two quaternary configurations is a prerequisite for the full expression of the alkaline Bohr effect.Among the different functional properties of to the peripheral tissues and the homoeostatic mammalian haemoglobins the alkaline Bohr effect is regulation of pH of extracellular fluids. However, of particular interest, as it concerns both 02 delivery despite its extensive study for more than 30 years, its Abbreviations used: Hb, haemoglobin; P50, partial molecular mechanism is still controversial (Kilpressure of 02 at half-saturation of haemoglobin; Bistris, martin et al., 1973;Matthew et al., 1979