[The alkaline Bohr effect: regulation of O2 binding with triliganded hemoglobin Hb(O2)3].

The processes of the proton concentration effect on the oxygen binding with triliganded human hemoglobin Hb(O2)3 have been studied by time resolved absorption spectroscopy. The pH-dependencies analysis carried out has shown that R-state alkaline Bohr effect was formed by two amino acid residues with pK = 7.3 +/- 0.1 and 9.1 +/- 0.1. It has been shown that oxygen affinity decrease at pH values above 8.5 could be caused by alpha 140-Tyr and beta 145-Tyr. The entrance and exit into/from the globin matrix is controlled by the same amino acid residues. On the strength of the experimental data the dynamics nature of the R-state alkaline Bohr effect has been proved.