354 Prof. H. E. Armstrong and Mr. E. Horton. [Mar. 3, 



the extent of 94 per cent., in 24 hours at 25°. At 37° the solution of the 

 Phaseolus glucoside was hydrolysed to the extent of only 4"5 per cent, in 

 24 hours and of 16"5 per cent, at the end of seven days; apparently, the 

 almond extract contained a very minute proportion of enzyme capable of 

 hydroly'sing this glucoside. 



Action of the Phaseolus Enzyme on Amygdalin. — A fact not brought out by 

 any previous observer is that the enzyme extracted from Phaseolus seeds* 

 acts but slightly on amygdalin. 



A solution (M/5) of amygdalin, containing 20 c.c. of a solution of the 

 enzyme prepared from Phaseolus seeds was hydrolysed only to the extent of 

 2"5 per cent, in 24 hours at 25°, whilst 4 per cent, underwent change in 

 24 hours at 37° and 12 per cent, in seven days.f A similar solution of an 

 equivalent amount of the Phaseolus glucoside was hydrolysed by the 

 correlated enzyme to the extent of 50"5 per cent, in 24 hours at 25° and of 

 77'5 per cent, in the same time at 37°. 



If, therefore, the view that tlie Pliaseolus enzyme contains both an a- and 

 a /3-glucase be accepted, this remarkable reciprocal behaviour of the two 

 enzymes to the two hydrolytes must be taken as an indication that almond- 

 emulsin also contains both an «- and a ;5-enzyme ; moreover, that the relative 

 proportions in which the two forms are present are reversed in the two 

 enzymes. On this supposition however, as almond-emulsin is without action 

 on methyl-«-glucoside, the a-enzyme it contains must be different from that 

 present in yeast maltase ! 



Action of the Phaseolus Enzyme on Methyl-a-giueoside and on Maltose. — From 

 the statement made by Uunstan, Henry and Auld that yea.«t n)altase 

 decomposes metliyl-a-glucoside and maltose nrore rapidly than does the 

 enzyme of Pliaseolus lunatas, it is to be inferred that these two compounds 

 are hydrolysed by the Phaseolus enzyme. We have not been able to detect 

 any trace of action, even wlien the substances were allowed to remain in 

 contact during several weeks. 



In a preliminary experiment in which an M/5 solution of methyl-«-glucoside 

 containing 20 c.c. of phaseolunatase solution {)er 100 c.c, was heated at 25° 



* Our preparation was made fi'om f^rouiid tJava beaii.s, simie of wliich were black, otlier.s 

 various shades of brown and a few white. The precipitate ])r<)duced by ah'ohol in the 

 aqueous extract, which liad been expo.sed over potasli to remove liydrogen cyanide, was 

 shaken up with about six times its weight of water. 



t lixperiments liave been recorded by Auhl ('('hem. Soc. Traua.,' 1908, vol. 93, p. 12G6) 

 which appear to show that the Phaseolus enzyme acts somewhat readily on amyj^daliu — to 

 the extent of as much as 34"5 per cent, within an hour. 



[The discordance Ijetwecii this result and our own is considerably reduced if allowance 

 be made for the diflerent ))r<)])ortions of the materials used ; nevertheless, the value is in 

 advance of any we have obtained. — April 9.] 



