640 



CATALASE ACTION 



the fact that the catalase was suspended in the water. In connection 

 with our own experiments we tried to determine the facts microscopi- 

 cally. 



Experiment 1. — The damaged piece of thallus was placed in sea water + a 

 trace of H2O2. Bubbles of oxygen originated only at the place where the piece 

 was cut. After a long time there was a very feeble activity on the surface ceasing 

 after about 2 hours. 



Experiment 2. — A similar piece of thallus was placed in distilled water + a 

 trace of H0O2. Oxygen originated immediately at the place where the piece was 

 cut. After about 3 minutes there was a strong reaction on the whole surface, 

 which lasted for about 50 minutes. 



There are two conclusions possible, which might explain these facts: 

 (1) catalase goes out by exosmosis; (2) catalase goes out through 

 the burst cell wall. 



While the second assumption may be possible, there is one fact 

 that can be explained in favor of the first assumption. If the cell 

 bursts, there is no reason why any catalase should remain in the cell, 

 as the enzyme is soluble in water. A fact that reminds one of exosmo- 

 sis is the short space of time within which the emigration of the 

 catalase is completed. It is improbable, on the other hand, that 

 large molecules diffuse out of the cells in which they occur. We 

 may suspect, therefore, that this enzyme at least is a simpler com- 

 pound than most of us have thought hitherto. 



Influence of Substrate Concentrations.— V^e considered one series of 

 experiments done with homogeneous material under the same con- 

 ditions. 3 gm. of Ulva were ground in a mortar to a very fine con- 

 sistency with 15 cc. of distilled water. The peroxide was previously 

 neutralized by 0.1 cc. of 0.1 n sodiimi carbonate solution per cc. 

 We found 



