THE OCCURRENCE OF LICHENASE IN. THE DIGESTIVE 
TRACT OF INVERTEBRATES. * 
By MINNA E. JEWELL anp HOWARD B. LEWIS. 
(From the RT of Physiological Chemistry of the University of Illinois, 
Urbana.) 
(Received for publication, November 19, 1917.) 
No animal enzyme has yet been found by which the hydrolysis 
of lichenin, the peculiar dextran of Cetraria islandica, may be 
accomplished. Of the vegetable enzymes, Saiki (1) has reported 
that the taka-diastase of Hurotiwm oryze and the inulase of 
Aspergillus niger were active in the hydrolysis of lichenin, while 
malt diastase was inactive, as previously observed by Brown (2). 
Examination of human saliva (1, 2, 3) and gastric juice (3), of 
extracts of the pancreas of the dog (1, 3) and ox (3), and of the 
intestine of the pig (1) for the presence of a lichenase have uni- 
_formly yielded negative results. In view of this resistance to: 
hydrolysis by the body enzymes of the higher animals, as pointed | 
out by Nilson (8), the problem of the utilization of lichens by 
animals, such as the reindeer, and in human dietaries offers 
many difficulties. Bacterial decomposition might be expected 
to play a role here, but:according to Saiki (1) cultures of Bacillus 
coli do not form reducing sugars from lichenin. | 
In connection with a Study of the fresh water crayfish, it 
was observed that extracts of the hepatopancreas possessed 
marked hydrolytic properties towards solutions of lichenin, and 
further investigations of certain other invertebrates disclosed the 
existence of lichenase in these animals. Accordingly, a system- 
atic search for the presence of lichenase in the alimentary tract 
of such vertebrate and invertebrate forms as were available - was 
undertaken. 
The lichenin used as a substrate was derived from three sources: 
(1) crude extracts of Iceland moss, (2) lichenin obtamed from 
* A preliminary account of this investigation was presented before the. ) 
Society for Experimental Biology and Medicine, New York, Dec. 20, 1916. © 
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THE JOURNAL OF BIOLOGICAL CHEMISTRY, VOL. XXXIII, NO. 1 
