OXYHEMOGLOBIN IN DILUTE SOLUTIONS 



143 



was made on the same haemoglobin solution and yielded the figure 

 17-5. 

 The ratio of these two velocity constants, 



132 



17-5 



= 7-5, 



should give the equihbrium constant of the reaction 



HbOa :^ Hgb + Og 

 indirectly, and this, as was pointed out at the commencement of the 

 chapter, should agree with the equihbrium constant as obtained from 



1-9 



1-7 



1-5 



"5 



~Q 



-o 



6 



^O. 



Ov 



0-1 0-2 0-3 



Fig. 43. Abscissa = time in seconds. Ordinate = log. of percentage of oxyhsemoglobin. 



Fig. 39, for it was determined from the same solution. That equi- 

 hbrium constant, in the units used above, worked out to 9-75. 

 Considering the magnitude of the errors involved this degree of 

 agreement is highly satisfactory. 



Stress has been laid upon the fact that all the determinations 

 necessary for the above comparison were carried out on the same 

 solution of haemoglobin. For this there are several reasons, two of 

 which may now be stated; the reduction phase, 



HbOg— »► Hb + O2, 

 unhke the oxidation phase, is very sensitive to the conditions under 

 which it takes place, notably, the hydrogen-ion concentration and 

 the temperature. 



Some more detailed information may be given on these relation- 

 ships before the chapter closes. 



Fig. 44 is similar to Fig. 43, but instead of showing the relation 



