322 BIOCHEMICAL GENETICS 



chain and a beta chain. In both of the chains the terminal amino acid is valine as in 

 human hemoglobin; the second amino acid in one chain is leucine, but in the other 

 chain is not leucine. We know there are two chains, but we do not know any more 

 than that about them. 



Commenting on the similarity of heme in all hemoglobins, let us call this a simi- 

 larity, or perhaps identity, of the chemical structure of hemes. We are talking in 

 theoretical terms about the synthesis of a protein molecule. We already know from 

 humans of the possibility of independent alpha-chain synthesis and beta-chain synthesis. 

 Let us remember further that in mice there are at least two independent genes which 

 affect the rate of synthesis of heme. Thus, before the total, complex, hemoglobin mole- 

 cule is formed, many kinds of genie action must occur. 



Dr. Bernstein : Dr. Popp, a number of methods that you elaborated on today 

 require the assumption that hemoglobins are quite stable. Inasmuch as changes in 

 oxygen concentration (oxygenation or partial oxygenation) of the molecule result in 

 changes in charge and solubility characteristics, I wonder if you would comment on the 

 relative stability of oxyhemoglobin, carboxyhemoglobin, and so forth, with particular 

 reference to species differences. Of course I am concerned with the mouse. 



Dr. Popp: Cyanmethemoglobin seems to be the most stable form of murine hemo- 

 globin. Although methemoglobin is quite stable, for many studies it is a less desirable 

 state in that the electrophoretic mobility and chromatographic behavior of methemo- 

 globin is slower than that of cyanmethemoglobin or carbonmonoxyhemoglobin. 



Murine carbonmonoxyhemoglobin is about twice as stable as oxyhemoglobin; 

 however, studies of Douglas et al. 285 and Anson et al. 33 suggest that the conversion of 

 murine hemoglobin to carbonmonoxyhemoglobin may be incomplete. Their data 

 show that 30 to 40 per cent of the hemoglobin remained in the oxyhemoglobin state. 

 This in itself is interesting, since hemoglobins of most mammals are readily converted to 

 carbonmonoxyhemoglobin by simply bubbling carbon monoxide into the solution of 

 hemoglobin. 



Dr. Russell: My impression, based on starch gels rather than on resin papers, 

 is that one sees dense spots but resolution is not good enough to test for identity of 

 hemoglobins in a mixture. Resolution may be better on resins; I would be glad to 

 try this method, but its suitability may depend upon the question being asked. 



Dr. Burdette: Is the wave length used 415 mu.? 



Dr. Russell: Yes. 



Dr. Popp: We have run an absorption spectrum from 220 through 900 mu. using 

 a Beckman automatic recording instrument. Areas of the spectra that looked slightly 

 different were examined more carefully, using a Beckman spectrophotometer. The 

 absorption spectra were indistinguishable even for hemoglobins of different electro- 

 phoretic character, for example, single and diffuse hemoglobins of strains C57BL and 

 101, respectively. 



