O-2-dependent K+ fluxes in trout red blood cells: the nature of O-2 sensing revealed by the O-2 affinity, cooperativity and pH dependence of transport



: Berenbrink M, Volkel S, Heisler N, Nikinmaa M

Publisher: CAMBRIDGE UNIV PRESS

: 2000

: Journal of Physiology

: JOURNAL OF PHYSIOLOGY-LONDON

: J PHYSIOL-LONDON

: 526

: 1

: 69

: 80

: 12

: 0022-3751

DOI: https://doi.org/10.1111/j.1469-7793.2000.t01-1-00069.x


4. O-2-stimulated K+ influx and efflux were strongly pH dependent. When the definition of the Bohr factor for respiratory pigments (Phi = Delta logP(50) x Delta pH(-1)) was extended to the effect of pH on O-2-dependent K+ influx and efflux, extracellular Bohr factors (Phi(0)) of -2.00 and -2.06 were obtained, values much higher than that for Hb (Phi(0) = -0.49). The results of this study are consistent with an O-2 sensing mechanism differing markedly in affinity and cooperativity of O-2 binding, as well as in pH sensitivity, from bulk Hb.



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