SOME PROPERTIES OF CATALASE 405 



2.2. Spectroscopic and Magnetochemical Properties 

 of Catalase and Compounds of Catalase 



The absorption bands of liver catalase have been found by various 

 authors (3J^,1390,US7, 2653,2659,2697, 3166) in somewhat different 

 positions, varying with the method used. By visual spectroscopy 

 the centers of the unsymmetrical bands are found to be shifted toward 

 the red as compared with the true position of the absorption maxima 

 (Theorell, 2778). The spectrum was found as follows: 



I, 629-622 (e^M = 10.8) II. 544-536 III, 506.5-500 



IV, 409-400 (e,„;vi = 145) V, 2«0-^266 m/z (IV > III > I > II) 



The quantitative extinction values are those given by Stern (2653). 



Agner (24) reports a much lower value for the extinction of the 

 Soret band IV (e„,!M = 78.5). Itoh (1390) made the queer obser- 

 vation that the absorption band at 406 m/i disappears when the 

 enzyme is treated with carbon monoxide. The band at about 270 m;u 

 is remarkably high; Stern and Lavin (2659) explain this by the rela- 

 tively greater contribution of the protein in catalase as compared 

 with hemoglobin. 



It should be noted that most of the spectroscopic studies were 

 carried out with liver catalase which, as will be seen below, contains 

 a somewhat varying amount of bile pigment hematin, differing in 

 this respect from erythrocyte catalase. 



Keilin and Hartree (H87) observed a shift of the absorption bands 

 caused by ammonia, not by other alkalis; catalase is thus evidently 

 able to form an ammonia compound. Theorell and Agner (28, p. 7; 

 2780) found that, at a lower 7>H, catalase becomes more greenish, the 

 absorption band in the orange shifting to 618 m/x and becoming 

 narrower and higher. By measurements of the effect of anions on 

 the intensity of the absorption at 610 van, Agner and Theorell (29) 

 have recently shown that at a pH above 4 the hematin iron of erythro- 

 cyte as well as of liver catalase has a hydroxyl ion bound to it as has 

 the iron of hemiglobin hydroxide. Anions can replace the hydroxyl 

 group : 



(FeOH) + X~ ;=i (FeX) + OH^ 



While relatively high concentrations of phosphate are required for 

 this reaction to proceed to a noticeable degree, acetate and particu- 

 larly fluoride and formate react at much lower concentrations. If 



^_ [FeOHl [X-| [H^l 

 [FeXI 



