390 ENZYMES 



, According to Posternack,* a large amount, 80-90 per cent, 

 of the phosphorus of certain seeds exists in the form of phytin ; 

 it occurs, for instance, in thegloboid portion of aleurone grains, 

 and the seeds which contain it also possess an appropriate 

 enzyme phytase for its decomposition into phosphoric acid 

 and inositol.f 



With regard to the formation of phytin little is known ; 

 Posternack considers that it is formed by the combination of 

 formaldehyde, produced in the early stages of photosynthesis 

 with phosphoric acid. 



The tenability of this opinion is obviously bound up with 

 the formation of formaldehyde in green leaves (q.v.). 



Phytin appears to be an acid calcium and magnesium salt 

 of inositol phosphoric acid which is a condensation compound 

 of inositol with six molecules of phosphoric acid.J 



MANUFACTURE OF ETHYL ALCOHOL. 



The action of yeast on sugar is made use of in the manu- 

 facture of ethyl alcohol, which substance is prepared from 

 potatoes, rice, and other grains rich in starch. The manu- 

 facture from potatoes is carried out as follows : Potatoes are 

 heated in closed vessels ( to 125-135 by means of super- 

 heated steam under a pressure of about 3 atmospheres ; by 

 suddenly releasing the pressure the potatoes are burst, and 

 are thus obtained in a finely divided state. The whole mass 

 is then thoroughly stirred up with malt at a temperature of 

 about 60, whereby the starch undergoes hydrolysis with 

 formation of maltose and dextrin. 



(C 6 H 10 5 ) n + H,0 -^HaOu + (C 6 H 10 5 ) X 

 Starch Maltose Dextrin 



After about one and a half hours the mixture is rapidly 

 cooled to 15 and mixed with yeast ; fermentation at once 

 sets in, accompanied by a considerable evolution of heat ; the 



* Posternack: "Compt. rend.," 1903, 137, 202, 337, 439. 



fCf. Suzuki, Yoshimura and Takaishi : "Bull. Coll. Agric., Tokyo," 1907, 

 7> 53- See also Rose : "Biochem. Bull.," 1912, I, 428. 



Cf. Neuberg : " Biochem. Zeitschr.," 1908, 9, 557 ; Winterstein : " Zeitschr. 

 physiol. Chem.," 1908,50, 118. See also Plimmer : "Biochem. Journ.," 1913, 

 7, 43; Boutwell : "Journ. Amer. Chem. Soc.," 1917, 39, 491; Posternack: 

 "Compt. rend.," 1919, 169, 37, 138. 



