Cytochrome Oxidases o/ Pseudomonas Aeruginosa 319 



If in Table I (p. 317) the total oxidase concentration is calculated according to these 

 more recent extinction coefficients, the stoichiometric ratio expected for 4(0,)/(« + a,) 

 IS 2-0 and the observed values given in line 4 of Table 1 would be multiplied by 1-3 in 

 the case of the value used at the Enzyme Institute and by 1-5 in the case of the value 

 used m this laboratory. It is apparent that these values of extinction coefficient lead to 

 closer agreement with the idea that both cytochromes a and a, are titrated under our 

 experimental conditions than does the older and less accurate value 



