. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HEMOGLOBIN EVOLUTION 231 lished data). That CO2 does not cause any special Bohr effect for hagfish hemo- globin is shown in Figure 3. Because the possible Bohr effect of hagfish hemoglobin is so small and occurs at almost one pH unit below the normal pH of hagfish blood (; Prosser ct ol, 1950; David Jensen, personal communication), it is reasonable to assume that it is of no physiological significance, especially as CO2 does not have any specific effect. Knowledge of the heat of oxygenation (AH°) of hagfish hemoglobin
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HEMOGLOBIN EVOLUTION 231 lished data). That CO2 does not cause any special Bohr effect for hagfish hemo- globin is shown in Figure 3. Because the possible Bohr effect of hagfish hemoglobin is so small and occurs at almost one pH unit below the normal pH of hagfish blood (; Prosser ct ol, 1950; David Jensen, personal communication), it is reasonable to assume that it is of no physiological significance, especially as CO2 does not have any specific effect. Knowledge of the heat of oxygenation (AH°) of hagfish hemoglobin enables one to predict the position of the oxygen equilibrium at any particular physiological 10 -y PoliS to tr etna sfov ft. «/» II V* prj • o * 0 Pco2 0 0 10 p FIGURE 3. Oxygen equilibria under a variety of conditions of hemoglobin solutions prepared from the blood of the California hagfish, Polistotrema stouti. Dashed lines are drawn to ap- proximate the oxygen equilibrium at and ° C. The solid line is drawn on the basis of data presented in Figure 1 in order to facilitate the comparison of hemoglobin solutions in the presence and in the virtual absence of CO-,. temperature. In addition, absence of a Bohr effect facilitates the evaluation of AH°, for corrections representing the effects of ionizations of heme-linked groups do not need to be applied. Using data presented in Figure 3, a value of AH° kcal. (one atmosphere of dissolved oxygen gas at the standard state) was obtained as in a previous study (Manwell, 1958a). This value of AH° is similar to those observed for hemoglobin of sheep (— kcal.; Paul and Roughton, 1951), the holothurian Cucumaria miniata (— kcal.; Manwell, 1958f), and adult and fetal spiny dogfish, Sqnalns siicklcyi ( to kcal.; Manwell, 1958d). This group of values for the heat of oxygenation of various hemoglobins is not. Please note that these images are extracted from scanned page i
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
