HaemoprotL'in of Purple Photosynthetic Bacten 

 Table 2. Extinction coefficients for rhp* 



(Newton and Kamen, 1956; Bartsch and Kamen, 1958) 



427 



* Values in this table corrected in proof; see Horio and Kamen, 1960. 



t pH = 4-75. 



% Specific extinction values are tabulated ; to calculate E^^ values, multiply R. rubrum 

 values by 26 and Chromatium values by 36. These values are provisional, awaiting more 

 accurate dry weight determinations. 



As previously shown for physical properties (Table 1), the two preparations 

 differ somewhat in light-absorption properties. A major source of error 

 which contributes to an estimated uncertainty of 10-15 % in the values quoted, 

 can be traced to the difficulty in determining dry weight of small amounts of 

 protein. The small differences in location of absorption maxima are to be 

 expected. Similar, and even greater, differences are characteristic of other 

 classes of haemoproteins. 



Metal Content 



The limited amounts of pure material available have led us to defer 

 determined attempts to establish the content of iron and other metals. We 

 have noted erratic and unreproducible results in the few attempts made with 



