Analysis and Interpretation of Absorption Spectra of Hacmin Chromoproteins 149 



conclusion appears justified that practically as good a result is yielded by the 

 new method as by the one used by Brode (1928). The latter's frequency 

 spacing of/= 12-28 was purposely retained in the analysis. It should be 

 pointed out that the writer's method yielded one extra band (number 34) at 

 the low-frequency end of the spectrum. This is explained by the fact that a 

 values, calculated from the left slope of the absorption curve were suflftciently 

 discrepant from each other to denote skewness and suggest the presence of an 

 additional component. 



Tentative Corollaries or Rules of the Analysis and Notation of Bands. 

 (a) The presence of bands in the absorption curves may be indicated either by 

 well-defined maxima, by inflections ('bumps') in the curve, or by regions of 

 relatively flat absorption. On the other hand, several component bands may 

 be merged together into an apparently single band or may be hidden in the 

 final 'summational' spectrum curve. These propositions can be demonstrated 

 by the summational results obtained with two or more neighbouring (over- 

 lapping) curves of the normal frequency type, (b) The positions of the 

 maxima in the determined absorption spectrum may be displaced from their 

 theoretically correct locations in the resolved components. Indeed, this is 

 an expected consequence of the overlapping of the component elements in 

 the proposed analytical method, (c) The analysis itself best discloses the 

 multiple components, and, as has alieady been stated, 'predicts' the possible 

 presence of hidden bands. Hence, certain component bands are represented 

 by prominent maxima in the spectra of all haemin chromoproteins, others 

 only in the spectra of some of the complexes or their derivatives (see Table 2). 



The descriptive notation used for a particular band in the complex spectra 

 may prove controversial. This matter need not be debated here. The historical 

 designations a and (i have been retained for the bands in the visible green 

 spectral region. Even this may be illogical, since bands are present in the 

 red and near infra-red spectral regions (Fig. 1). The a and /5 bands are 

 deduced by our analysis to have a structural significance differing from the 

 main frequency distributed series. For the latter, which includes the Soret 

 and ultra-violet bands the designations y and 6 appear inappropriate, and 

 they will be assigned a number, n, which is an integer (3, 4, 5, 6, 7, etc.) 

 based on the frequency spacing v x 10"^ = 40. Thus 6 x 40 = 240, the 

 wavenumber location or a of the y or Soret band; 8 x 40 = 320, the 

 postulated location of the d band (Table 2, Figs. 5 to 10). 



EXPERIMENTAL 



Contribution of Haemin to Over-all Spectroscopic Character of the Haemin 

 Chromoproteins. In Tables 1 and 2 and in Figs. 1, 2 and 5 to 11, which with 

 their legends are largely self-explanatory, the basis for the analysis of the 

 spectra and deductions drawn therefrom is furnished. Attention may be 

 directed to several points. 



