Oxyhemoglobin crystals

Oxyhemoglobin crystallizes much ntore easily than hemoglobin and may be prepared in the following way. 

In contrast to the simplicity of these results it should be mentioned that in some way the crystal structure of reduced hemoglobin is different. Attempts to convert crystals of acid methemoglobin into reduced hemoglobin and crystals of reduced hemoglobin into oxyhemoglobin are always accompanied by a complete break up of the original crystal structure and recrystallization in a new form occurs (Haurowitz, 24). It is not yet established whether these differences are only important in considering the structures of the crystals or whether they are reflected in the reactions of these compounds in solution. 

The solubility of hemoglobins of various species varies widely. For example, the oxyhemoglobin of rat often crystallizes out spontaneously when the red cells are hemolyzed, but human and sheep oxy-... 

---