290 



VI. HEMOGLOBIN 



of K, the constant of partition between oxygen and carbon monoxide. Log 

 K changes by about 0.05 per angstrom unit shift in the band (See Fig. 1, 

 Chapter VII). Similar relations have been found to exist between the 

 logarithms of the affinity constants of the hemoglobin of some species for 

 carbon monoxide and the position of the a band of the carboxyhemoglobins, 

 and between the variation of the affinity of hemoglobin for oxygen with 

 temperature and the temperature variations of the positions of the a absorp- 

 tion band of oxyhemoglobin (Brown and Hill, 351, cf. Fig. 12). 



15 



Warm 



10 5 



brilFT IN BAND. A 



Cold 



Fig. 12. Variations of band position and oxygen affinity with temperature (after 

 Brown and Hill, 351). C is the concentration of O2. 



Although this relationship between affinity and spectrum is not yet 

 understood {cf. Chapter VII), it would seem extremely unlikely that 

 such agreement between affinity and band shift for both the oxyhemo- 

 globin and the carboxyhemoglobin compound would exist if the gases 

 were combined at different places on the hemoglobin molecule. 



