M. J. Blish 557 
EKxperiment II. 
In order to obtain a more satisfactory idea of the nature of the 
peptide linkings left in solution after the copper treatment, a 
portion of Solution X from flour A was acidified and treated with 
phosphotungstic acid. A considerable precipitate formed which 
contained 40.91 per cent of the total nitrogen in the solution not- 
withstanding the fact that when the original water extract of flours 
is treated with phosphotungstic acid no more (and often less) 
nitrogen is precipitated than by the copper method. However, 
when Solution X was subjected to a further treatment with cop- 
per, as in the first removal of the proteins, no more nitrogen was 
precipitated. Furthermore, when a portion of Solution X was 
mixed with about nine times its volume of 95 per cent alcohol, 
30 per cent of the total nitrogen in the solution was precipitated, 
along with the dextrins and other carbohydrates insoluble in 
alcohol. These facts strongly suggest the presence of peptide 
linkings of a less complex nature than true protein. The phos- 
photungstic acid precipitate was filtered off, washed with a solu- 
tion of phosphotungstic and hydrochloric acids, and hydrolyzed 
for about 12 hours with strong hydrochloric acid, after which 
ammonia and amino nitrogen were determined. Amino nitro- 
gen was also determined in the filtrate from the phosphotungstic 
acid precipitation. Although the determinations were made on 
small amounts of material, they were confirmed by several 
closely agreeing duplicates and blanks on each analysis, the result 
being reported in Table III. 
TABLE III. 
Constituent determined in terms of total N in Solution X. Flour A. 
per cent. 
INS DT ECIMAIsLeGcUy SICONOh esis) 56. Pek er ee ed - 80.00. 
N precipitated by further treatment with CuSO, and NaOH.| ~— None. 
N precipitated with phosphotungstic acid.................-. 40.91 
Mr MATING NCI OONICLON, Sc: 6h Stas nan via eat we ss ko 4 we 64627 
Total amino N in filtrate from phosphotungstic acid pre- a 
BEDE ore oe Pde Che Onan hk LS CUO a co 4.81 
Amino N from exposed amino groups of peptides (by dif- 
Ree Ce WO Notre! nee eis Ohana er mae a 5 a)51s x's AS ashe 2 1.81 
Ammonia N after hydrolysis of phosphotungstic acid pre- 
oipitate........ REE se ery La hs 0 ae hoe eR Fare 5.71 
PME ATLON NVOTOMY Sis. 0. Ce lide Say teria koa eee ot ols 14.30 
