Oct. 21, 1918 



Catalase and Oxidase Content of Seeds 



161 



mination; (4) same as the last but only the filtrate passing through a 

 porous clay (fine Berkefeld) filter used in the run. 



Tabi,^ XXV. — Solubility of catalases of amaranthus and fohnson grass seeds 



Seed and treatment. 



Amaranthus retroflexus: 



Powder 



Powder shaken with water i hour at 25° C 



Filtered extract (C. S. & S. filter No. 595) 



Filtered extract (Berkefeld) 



Johnson grass : 



Powder 



Powder shaken with water i hour at 2 5° C . . 



Filtered extract (C. S. & S. filter 595) 



Filtered extract (Berkefeld) 



In amaranthus shaking the powder with water for one hour reduced 

 the catalase noticeably. The catalase of this seed seems to be sensitive 

 to such agitation. Filtering through either the filter paper or the 

 Berkefeld filter reduced the activity somewhat more than 50 per cent, 

 the latter showing slightly the greater reduction. In the Johnson grass 

 shaking for one hour with water gave scarcely any reduction in activity, 

 while filtering through the filter paper gave a reduction of about 70 per 

 cent, and filtering through a Berkefeld filter a reduction of about 86 

 per cent. 



On this basis somewhat more than 50 per cent of the catalase of amaran- 

 thus seeds is insoluble, while 70 per cent or more of that of Johnson grass 

 seeds is insoluble. This, however, takes no account of the portion of 

 catalase that may be chemically united with or adsorbed by the insoluble 

 seed powder and the filters. It is likely also that the catalase complex is 

 in the colloidal state and that the portion in the lower degrees of disper- 

 sion is held back by the fine filter, especially after it is blocked by colloidal 

 materials. The proportion of soluble and insoluble catalase in these two 

 seeds is not such as to throw any light on the relative time and heat 

 stability of the catalases of them. 



OXIDASE IN SEEDS 



All oxidase determinations were made at 30° C. in the Bunzell simpli- 

 fied apparatus (10) either with or without caustic boats suspended from 

 the manometer for absorption of carbon dioxid. All the material used 

 was ground so that it would pass through bolting cloth with 70 or 80 

 meshes per inch. Seeds of Johnson grass, Sudan grass, or Tunis grass- 

 sorghum hybrid, when used without removing the scales, were ground 

 until about 85 per cent by weight pass through the bolting cloth, the 

 remaining 15 per cent being discarded. 



