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XXVIII. 



ON THE ACTION OF PECTASE. 

 By NIGEL G. BALL. 



[communicated by professor H. H. DIXON, SC.D., F.R.S.] 

 [Read November 24, 1914. Published January 7, 1915.] 



Introduction. — The enzyme which causes the eoag'ulation of vegetable 

 saps containing pectin was discovered by Fremy (9) in 1840. At present 

 there is a certain amount of confusion in the terminology of this and related 

 enzymes. Euler (8) applies the name peetase to the enzyme wliich converts 

 pectose into pectin, and calls the enzyme which coagulates pectin, pectinase. 

 Other writers retain the original name peetase for the enzyme whicli coagulates 

 pectin, and in the following account this enzyme will be denoted by this 

 name. With regard to the two other related enzymes, the most generally 

 accepted terminology seems to be that in which the enzyme whicli liydrolyses 

 pectin to d-galaetose and 1-arabiuose is called pectinase, and the enzyme 

 which converts pectose into pectin, pectosinase. 



Previous workers on this subject — Fremy (9), Bertrand and Mall^vre 

 (1),(2), (3), Bourquelot (4J, and Bourquelot and Herissey (5),(6) — simply 

 allowed coagulation of the pectin by the enzyme to take place under various 

 conditions, and noted the time taken before this was complete. 



In the present research an attempt was made to study the action of 

 peetase by observing the electrical conductivity of a solution of pectin 

 when acted upon by the enzyme, and also by determining the change in 

 viscosity. 



Preparation of Materiah. — The pectin used in this research was obtained 

 exclusively from the roots of the carrot, Baucus carota. The first extraction was 

 based on a method suggested in Browne's "Handbook of Sugar Analysis" (7) 

 for obtaining pectin from the juice of ripe pears. The chopped-up carrots 

 were put into a can and steamed in a Koch's sterilizer for about forty-five 

 minutes, and the juice was tlien squeezed out and filtered under reduced 

 pressure. A little oxalic acid was added to precipitate calcium, and a little 



SCIENT. PROG. K.D.S., VOL. XIV., NO. XXVIII. 3 L 



DEC 14 1915 



