1915] 



DAVIS ENZYME ACTION IN MARINE ALGAE 827 



Catalase, so wide-spread in all plant tissues, is found here 

 in all the forms investigated except Mesogloea. The "reds" 

 prove more active than the " browns," and these latter slightly 

 more active than the ' ' greens. ' ' No alga is strikingly active, 

 however, when compared with potato leaf tissue. Strangely, 

 Viva, most active in regard to the other enzyme groups, is 

 one of the least so here. 



General Discussion and Conclusions 



The data obtained in the foregoing investigation serve to 

 show that the number of enzymes in the algae that can be iso- 

 lated, by standard methods at least, is quite limited. This is 

 especially true of the " browns," in two forms of which, 

 Ascophyllum, and the Fucus of the earlier study, such action 

 is limited to catalase alone. In this group the demonstrable 

 carbohydrases are restricted to very slowly acting diastases 

 in Laminaria; in neither Ascophyllum nor Mesogloea is there 

 the slightest trace of what might be termed carbohydrate 

 hydrolysis. Moreover, negative results are obtained in these 

 forms for most of the other enzymes sought. Laminaria 

 shows lipases and catalases (it was not tested for proteolytic 

 or nuclease activity), and action in Mesogloea is restricted to 

 lipases and proteinases, both tryptic and ereptic. On the 

 other hand, very general enzymic activity is demonstrable in 

 the "greens" and the "reds" — diastases, dextrinases, lipases, 

 proteinases (tryptic and ereptic), nuclease, and catalase being 

 isolated from the crushed tissue. Oxidase is shown present 

 in one ' ' red, ' ' Agardhiella, and in one ' ' green, ' ' Viva. Such 

 action, as a whole, appears a little more rapid in the "reds" 

 than in the "greens," but no enzyme stands out as being 



.fie for either a group or an alga within 



The carbohydrases demonstrated are restricted in their 

 action to those hydrolysing starch, dextrin, glycogen, and 

 laminarin of the polysaccharides used as substrates, and in 

 Laminaria, such action was further limited by a failure to act 

 upon glycogen. In no case, in any member of the three groups 

 was there evidence of disaccharides being attacked. While 



