154 



David L. Drabkin 



for a. The locations and relative densities of the bands are very suggestive of 

 those found in the spectra of ferrohaemochromes, like pyridine and globin 

 ferroprotoporphyrins (see Fig. 17 and Drabkin, 1937, 1938). It is difficult to 

 regard this analytical result as pure coincidence. It is at the least highly 

 provocative, revealing as it does fundamental similarities in the spectrally 



^ 80 



MHbCN 





(■-;4o v 



y^= Il5e" 243 

 I. -3001 



yj,= 3IOe -lozo 



(x-360) 



yg=3l'3e 360 



(x-120) ' 



y^= 100 e 7go~ 



500 



Vu X 10" 



Fig. 8. The graphic-mathematical analysis of the absorption spectrum curve of 

 cyanmethaemoglobin (from dog haemoglobin). The continuous solid line is the 

 absoqDtion spectrum obtained experimentally. The broken line represents the 

 summation of the individual component elements or bands (solid dotted lines) of 

 the normal frequency form, derived by the writer's method of analysis. The 

 bands are numbers 3 to 7 in an equally spaced, frequency distributed series, with 

 Vq X 10~^ = 60. The summation of the resolved component bands is given by 

 the equation inserted in the figure. The equations y^ to J7 (insert in figure) are 

 for the respective components, with the applicable values for a and 2a- sub- 

 stituted in equation 1 (see Methods). 



divergent visible region of haemin-protein spectra. The single band of 

 deoxygenated haemoglobin at 555 m/< can be similarly resolved into bands 

 4, a, /? and 5. 



To summarize, it may be concluded from the graphic-mathematical analysis 

 that (1) the absorption spectra of all haemin chromoproteins and their 

 derivatives (both oxidized and reduced) are fundamentally similar, (2) the 

 a and /5 bands have a different origin from bands 3 to 11 of the equally spaced 

 frequency distributed series, and (3) the differences in the spectrum curves 

 (largely evident in the visible spectral region) are an expression of the relative 

 densities or intensities of the absorption bands in the different compounds 

 (Drabkin, 1937, 1938, 1941a; Table 2 and Figs. 10 and 12). 



