144 



David L. Drabkin 



verified by the finding of a definite maximum at 820 m/t in the spectrum of 

 methaemoglobin hydroxide and at 314 mjLi in the spectrum of ferrocytochrome 

 c (Drabkin, 1941a). The maximum at 314 m/< was later designated as the 

 6 band (cf. Theorell and Nygaard, 1954; Tsou and Li, 1956; Morton, 1958). 

 The very brief past reports embracing this phase of our studies have 

 presumably escaped notice by those more recently concerned with the analysis 

 of the spectra of chromoproteins (Williams, 1956; Morton, 1958). In this 

 communication a more complete description of our graphic analytical method 

 will be supplied, together with an assembly of absorption data relevant to an 

 interpretation of the spectra of haemin-protein complexes and possibly to 

 the development of the theory of molecular spectra. 



MATERIALS AND METHODS 

 Materials 



The haemoglobins were crystallized preparations (Drabkin, 1946, 1949a), 

 the solutions of which were rendered 'salt-free' either by dialysis or passage 

 through 'Deeminac 16-4' resin (Drabkin, 1954). The cytochrome c was 

 prepared from horse heart by Tint and Reiss (1950), and by our analyses 

 (see below) was 96 % pure, with reference to 0-43 % iron content. 



Methods 



Spectrophotometry. Most of the more recent measurements were carried 

 out with the Beckman DU instrument, but in the earlier work the Hilger 

 Spekker photometer and medium quartz spectrograph were used. When other 

 types of instrumentation such as recording spectrophotometers were em- 

 ployed, this will be indicated in the legends to the figures. 



Table 1 . f max of cyanide derivatives in the direct determination of 



HAEMIN IRON 



* £max, the millimolar extinction referred to 1 milliatom of iron, 

 t Iron determined independently as ferrous 1 : 10-phenanthroline (Drabkin, 1941b). 

 % May be rounded out to 16,500. 

 § Provisional. 



II Sample was 96% pure on basis of 0-43% of iron, or 91-6% pure on basis of 0-45; 

 of iron. 

 H Iron content of a-chlorohaemin. 



