EXPERIMENTAL. 91 



been proved to have no foundation, it would be desirable to return to Taddei's 

 original name and in future call this protein zymon. Unfortunately this 

 name is derived from the Greek word C^, a ferment, and, as the results of 

 this investigation show that the supposed ferment-changes do not occur in 

 the formation of gluten, this name is undesirable. As this protein is espe- 

 cially characteristic of gluten, it seems appropriate to call it glutenin, a name 

 suggested by Prof. S. W. Johnson. 



HYDROLYSIS OF GLUTENIN. 



The large quantity of glutenin which was required for the quantitative 

 determination of its decomposition products was prepared from the residue of 

 the wheat gluten after extracting the gliadin with alcohol. This residue was 

 dried at room temperature and then ground to a powder, which was extracted 

 first with absolute alcohol and then with ether as long as either solvent re- 

 moved anything from it. The alcohol was then removed at room temperature 

 and the residual powder treated with just enough 0.2 per cent solution of 

 potassium hydroxide to dissolve it. The resulting turbid solution was then 

 filtered perfectly clear and neutralized with very dilute hydrochloric acid. 

 The precipitate produced was extracted with 70 per cent alcohol as long as 

 any gliadin was removed, then thoroughly dehydrated with absolute alcohol, 

 and dried over sulphuric acid. 



940 grams, equal to 839.32 grams of glutenin, ash and water free, were 

 hydrolyzed by heating for several hours on a water-bath with a mixture of 

 950 cc. of concentrated hydrochloric acid and 950 cc. of water. After standing 

 over night, the solution was boiled on an oil-bath for 9 hours, and then 

 saturated with hydrochloric acid gas. By the same treatment as that applied 

 to gliadin (p. 71) 202.73 grams glutaminic acid hydrochloride, equal to 

 162.40 grams of the free acid, were obtained. Recrystallized once from 

 concentrated hydrochloric acid, this melted at 198. 



Chlorine: 0.5386 gram substance gave 0.4211 gram AgCl. 



Nitrogen: 0.5911 gram substance gave NH 3 = 4.53cc. HC1 (i cc. HCl = o.oi gram N)_ 



Calculated for C 5 H 10 O i NCI, Cl 19.35, N 7.65 p. ct. ; found, Cl 19.33, N 7.66 p. ct. 



The united filtrates and washings were concentrated to a sirup on a water- 

 bath under reduced pressure and the hydrochlorides of the amino-acids 

 esterified three times, as in the case of gliadin. The hydrochlorides of the 

 esters were neutralized and the free esters shaken out with ether, as for 

 gliadin. After drying the ether solution of the esters with potassium car- 

 bonate, it was kept 2 days over anhydrous sodium sulphate. The ether 

 was then removed by distillation from a water-bath at atmospheric pressure 

 and the esters distilled, with the results shown in the table on page 92 for 

 distillation A. The undistilled residue weighed 211.5 grams. 



