The different effects of pH and NaCl on individual O2-binding properties ofaandbsubunits within liganded tetramer and dimer of human hemo-globin (HbA) were examined in a number of laser time-resolved spectro-scopic measurements. A previously proposed approach [Dzhagarov BM & Lepeshkevich SV (2004)Chem Phys Lett390, 59–64] was used to determine the extent of subunit dissociation rate constant difference and subunit affinity difference from a single flash photolysis experiment.
