MUCINASE IN YAM. 



Tetsutako Tadokoru. 



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Yam yields a mucilaginous substance when grated and extracted with water. 

 The chemical nature of this slime was, for the first time, studied by J. Isliii'^, and 

 later by Prof. K. Oshima and the author -' who proved conclusively that the yam 

 slime belongs to a class of mucins. 



As the occurrence of mucinase or mucin coagulating enzym is not yet known 

 in the \-egetable kingdom while its presence in the animal kingdom has been reported 

 b\' Roger, Tremolliens and others '', it seemed of great interest to me to investigate 

 whether or not the mucinase is present in the yam which contains mucin. 



As material for my stud\-, the tubers of Dioscorca Batatas Dociic were taken 

 and grated as thoroughly as possible, mixed with five volumes of water and then 

 allowed to stand for several hours until starch granuls and other substances settled 

 at the bottom of the vessel. The thick liquid thus obtained was used for the follow- 

 ing experiment. 



1. Elucidation of enzymic nature. 



At the beginning of the experiment, three scries of bottles were prepared, each 

 containing a definite volume of the thick liquid of mucin. To the two series Avcre 

 added a few drops of dilute solution of calcium chloride and toluol, while to the 

 other only toluol was added. The one series of the former and the later were kejjt 

 in a thermostat at 30° C for several hours. The other series of the former were 

 kept in an ice bo.x for the same hours. 



Among the series of bottles kept in a thermostat, the following phenomena 



1) Bull. Coll. Agric, Imp. Univ. Tokyo, 2, (97-100.) 



2) Jour. Coll. Agric, Tohoku, Imp. Univ., Sapporo, Japcin. IV, 6, I9II (243-249) and V, II, 1913 



(5S-7-)- 



3) Oppenheimer, C. — Die Fermente und ihre Wirkungen, spezieller Teil. 3. Aufl. 1909 (336- ) 



