1915] 



DAVIS — ENZYME ACTION IN MARINE ALGAE 



797 



portions being removed and sugar determinations made at 

 the definite intervals noted in table v. 



The carbohydrases in this form appear to be limited to those 

 acting on starch and dextrin, and with these the hydrolysis 

 proceeds much more slowly than was true with either of the 



preceding 



* ' greens. ' ' 



The lower temperature at which the 



hydrolysis occurred does not explain completely the lessened 

 action. Inhibiting substances or else an actually smaller con- 

 centration of the enzyme seem to be important factors. 



table v 



THE ACTION OF A "DIFFUSION-EXTRACT" FROM AIR-DRIED LAMINARIA TISSUE 



UPON CERTAIN CARBOHYDRATES 



Substrate 





Sugar as glucose in 5 cc. 



mgms. 





15 dc 



tys 



45 days 



75 days 



100 days 



Starch 



Trace 



Trace 

 Trace 



3.25 

 4.1 

 Trace 



• • * • 



• • ft • 

 ft ■ ft ft 



ft ft ft ft 



4.7 



6.85 



Trace 



Trace 



Trace 



ft ft # ft 



Trace 



6.5 



Dextrin 



8.3 



Glycogen 



Trace 



Inulin 



A ft ■ 



A 



Trace 



Sucrose 



• • ft 

 ft ft • 



• m m 



. . . 



• 



• 

 • 



Trace 



Lactose 



■ ■ ■ ■ 



Maltose 



^F ^r ■ w 



Trace 



Another series (table vi) of flasks was set up with the same 

 form, using a ' ' diffusion-extract ' ' from the fresh tissue. Ten 



cc. of this diffusion represented 6 grams of the Laminaria 



pulp. In addition to the usual substrates, .5 per cent lamin- 



arin was used. Toluene was added and the flasks maintained 



for 60 days at room temperature ( 22-23 °C). 



TABLE VI 



THE ACTION OF A'DIFFUSION-EXTRACT" FROM FRESH LAMINARIA TISSUE UPON 



CERTAIN CARBOHYDRATES 



Substrate 

 100 cc. 





Sugar 



as glucose in 5 cc. 

 mgms. 





7 days 



15 days 



30 days 



45 days 



60 days 





Trace 

 Trace 

 Trace 



Trace 



Trace 



2.4 

 Trace 



2.7 



3.6 



3.9 



Trace 



Trace 



Trace 



4.2 



5.15 



5.4 



Trace 



Trace 



Trace 



Trace 



5.35 



Dextrin 



7.40 



Laminarin 



5.65 



Glycogen 



Trace 



Inulin 



Trace 



Sucrose 



Trace 



Lactose 





Maltose 



Trace 



