THE ALKALINE BOHR EFFECT - CONTROL OF THE OXYGEN-BINDING WITH TRILIGANDED HEMOGLOBIN HB(O-2)(3)

The processes of the proton concentration effect on the oxygen binding with triliganded human hemoglobin Hb(O-2)(3) have been studied by tim eresolved absorption spectroscopy. The pH-dependencies analysis carrie d out has shown that R-state alkaline Bohr effect was formed by two am ino 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 s trength of the experimental data the dynamic; nature of the R-state al kaline Bohr effect has been proved.