SUMMARY OF SPECTROSCOPIC PROPERTIES 



227 



V, Holden considers a high Soret band evidence of an intact porphyrin 

 ring structure as well as of the distribution of the absorbing molecules 

 outside or nearly outside each other's radius of action as far as optics 

 are concerned. The lower Soret band of acid hematin and (to a 



500 



100 



10.0 



0.10 



0.010 

 0.005 



900 800 700 600 500 



WAVELENGTH, m^ 



400 



300 



Fig 3. Absorption spectra of carboxyhemoglobin and hemoglobin 

 drawn from data of B. L. Horecker.* 



smaller extent) of hemiglobin hydroxide according to this view 

 indicates less effectiv^e separation of the prosthetic groups and a 

 certain degree of aggregation. 



In an extension of the scheme of Theorell {2775), (cf. Chapter V) 

 we may superficially classify the absorption spectra of these com- 

 pounds in the visible part of the spectrum as follows: 



TheorelVs Class IV 



Ferrous compounds with covalent bonds and with two absorption bands 

 in the green, the longer wave band being referred to as the first. 



*A composite graph of the absorption spectra shown schematically in Figures 2 and 

 3 will be found in the Appendix. 



