1913-14.] Enzymatic Peptolysis in Germinating Seeds. 
113 
X. — Enzymatic Peptolysis in Germinating Seeds. By Dorothy 
Court, B.Sc., Carnegie Research Fellow. Communicated by 
Professor E. Westergaard. 
(Read December 15, 1913. Revised MS. received February 10, 1914.) 
In a previous paper ( Proc . Roy. Soc. Edin., vol. xxxi. p. 342) a method was 
described for measuring small degrees of enzymatic peptolysis, and in a 
subsequent paper {Proc. Roy. Soc. Edin., vol. xxxii. p. 251) the conditions 
were dealt with under which such experiments could be carried out with 
the greatest possible guarantee of sterility combined with the least inter- 
ference with the reaction. 
The intention was to employ these methods for the purpose of pursuing 
the main object of research — the activation of zymogens in germinating 
seeds — and it was accordingly decided to carry through a series of ex- 
periments on germinating barley. This material was selected on account 
of the readiness with which it may be obtained. 
The presence of proteolytic and peptolytic enzymes in germinating 
barley has been previously described by Weis {C. R. Carlsberg Lab., vol. v. 
p. 127), Vines {Ann. Bot., xvi. 1), and Abderhalden and Dammhahn {Zeit- 
schrift fur physiol. Chemie, lvii.). 
Weis, working with a watery extract of crushed germinated barley, 
found evidence of proteolytic as well as peptolytic activity, and it was 
therefore decided to use a similar extract in some preliminary experiments. 
For this purpose 900 grms. of material were crushed in a mincing 
machine and extracted with 700 c.c. chloroform w r ater for twenty hours. 
The liquid was expressed in a hand-press, filtered, neutralised with sodium 
bicarbonate, and divided into three portions. One of these was made 
slightly acid ( = '2 per cent, lactic acid), one was made alkaline ( = T per 
cent. NaHCo 3 ), and one remained neutral. One gramme of Pepton Roche 
was dissolved in 10 c.c. of each of these preparations, T c.c. chloroform 
added, and the mixture incubated at 37°. It was somewhat surprising to 
find that though the digestion was carried on for several days no deposit 
of tyrosin was obtained. 
At the same time another experiment was carried out with the same 
material for the purpose of determining the relative activities of the 
embryo and endosperm of the seed. The embryos were carefully dissected 
vol. xxxiv. 8 
