[Vol. 2 



830 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



of the algae is also probably slower than that of the higher 

 plants and one might expect, a priori, the enzymes also to be 

 less rapid in their action. Although the algal enzymes may 

 be inherently slow, it seems that there may also be substances 

 set free on the death of the cell which either partially or en- 

 tirely inhibit enzyme action. The writer has found evidence 

 in some preliminary experiments, that the action of taka 

 diastase upon starch is directly proportional to the amount 

 of free tannin present. In connection with this, it was also 

 found that Ascophyllum had a ' * tannoidal ' ' content of 1.1 

 per cent of the dry weight. It is possible that such tannoids, 

 if in an uncombined state, may after the death of the cell unite 

 with an enzyme to throw it out of the sphere of action. That 

 diastases are demonstrable in tissues having a high tannin 



r> " *"& 



content may perhaps be explained on the basis that they are 

 bound up in such a way as to render them incapable of uniting 

 with the ferments. Still other organic inhibiting compounds 

 may be present, and the point opens up a very interesting 

 problem concerning inhibition, not only in algal tissues, but 

 in those of many higher plants as well. 



Summary 



1. Using standard methods of enzyme isolation and de- 

 termination, the following enzymes have been found in fresh 

 or dried algal tissue : 



a. Carbohydrases hydrolysing the polysaccharides, 

 starch, dextrin, glycogen, and laminarin, but not those 

 hydrolysing the several disaccharides employed as 

 substrates. 



b. Lipases acting upon neutral fats but not upon the 

 esters of the lower fatty acids. 



c. Proteinases (tryptic and ereptic) acting best under 

 neutral and alkaline conditions. 



d. Nucleases. 



e. Oxidases and peroxidases (in but two forms — Agard* 

 hiella and Ulva). 



f. Catalases. 



