. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 230 CLYDE MANWELL Between pH and hagfish hemoglobin in solution shows no detectable Bohr effect. Outside that pH range a significant decrease in oxygen affinity occurs; however, this effect appears to be a prelude to more drastic changes (methemoglobin formation and decrease in solubility), which become apparent several hours after equilibrium measurements. This is in contrast to the solutions at intermediate pH which are stable for days and display identical oxygen equi- libria when re-analyzed one or two days after
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 230 CLYDE MANWELL Between pH and hagfish hemoglobin in solution shows no detectable Bohr effect. Outside that pH range a significant decrease in oxygen affinity occurs; however, this effect appears to be a prelude to more drastic changes (methemoglobin formation and decrease in solubility), which become apparent several hours after equilibrium measurements. This is in contrast to the solutions at intermediate pH which are stable for days and display identical oxygen equi- libria when re-analyzed one or two days after the original measurements (see Figure 1). No Bohr effect was observed for erythrocyte suspensions at pH's above neutrality; however, paralleling the behavior of hemoglobin in solution, a slight oxygen affinity decrease occurs at acid pH's. The effect was shown not only 100 0 50 X o Polistotrenta. stoi/ti. PH 0 10 20 Partial Pressure of 30 I (mm. FIGURE 2. Oxygen dissociation curves of erythrocyte suspensions of the California hagfish, Polistotrema stouti, at two different pH's, showing the possible very slight Bohr effect. Erythrocytes in phosphate-buffered saline; no Karo present. Temperature = 20-21° C. by the partially clarified suspensions (Fig. 1), but also when no Karo was present (Fig. 2). In contrast to hemoglobin solutions such acidic erythrocyte suspensions were stable, possibly because of the presence of cellular reducing systems able to reduce any methemoglobin. The observed decrease in oxygen affinity could rep- resent a very small Bohr effect; however, until it is shown that the decrease in oxygen affinity is rapid and entirely reversible, the possibility of slight denaturative changes in the protein cannot be overlooked, especially in view of the results obtained for hemoglobin solutions. The presence of CCX specifically decreases the oxygen affinity, in addition to its effect resulting from the increase in acidity, for hemoglobin of the horse (Mar- g
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