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, 
Ulva, 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. Lamaria 
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,’’ Agardiella, and in one ‘‘green,’’ Ulva. Such 
action, as a whole, appears a little more rapid in the ‘‘reds’’ 
than in the ‘‘greens,’’ but no enzyme stands out as being 
specific for either a group or an alga within a group. 
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. Inno case, in any member of the three groups 
was there evidence of disaccharides being attacked. While 
