212 Hydrolysis of the Soluble Protein of Swede Turnijys 



contain 0-850 grm. of that acid and 1-877 grms. of aspartic acid. 0-4066 

 grm. of glutaminic acid was recovered from the copper salt and 0-44:3 grm. 

 obtained as the hydrochloride, making a total weight of 0-8506 of 

 glutaminic acid. Thus all the glutaminic acid had been separated from 

 the mixture. The aspartic acid separated as the copper salt weighed 

 1-48 grms. The remainder of the aspartic acid was contained in the 

 mother Hquor from the glutaminic hydrochloride, and its weight was 

 0-841 grm. — 0-443 grm. = 0-397 grm. The total weight of aspartic acid 

 recovered is 1-48 + 0-397 = 1-877 grms. Thus all the aspartic acid 

 had also been isolated from the mixture. 



Tyrosine. 



The filtrate and washings from the precipitate of calcium salts 

 were evaporated down. The residue had been allowed to stand for 

 three weeks under alcohol, during which time some insoluble substances 

 had separated out. These were filtered off. The calcium was removed 

 quantitatively by oxahc acid and the filtrate and washings made up to 

 a litre. 250 c.c. of this were taken as a test portion, made neutral 

 to htmus by addition of caustic soda solution (its acidity was due to 

 the hydrochloric acid liberated by the removal of the calcium) and 

 concentrated on the water bath to crystalUsing point. Upon coohng 

 a crop of crystals was removed. This was redissolved iu water, boiled 

 with animal charcoal and recrystalhsed. 



Weight of tyrosine obtained = 0-11 grm 



— 0-44 grm. in the htre. 



The insoluble substances filtered off were found to give the Millon 

 reaction, so they were treated for tyrosine. They were dissolved in 

 water and the calcium removed quantitatively by oxalic acid. The 

 filtrate was decolourised by animal charcoal and concentrated. Two 

 crops of crystals were removed weighing 0-78 grm. The crude tyrosine 

 was recrystalhsed from dilute ammonia. The pure tyrosine obtained 

 weighed 0-52 grm. 



0-1448 grm. gave NH3 equal to 7-9 c.c. N/10 acid 



= 0-01106 grm. nitrogen 

 = 7-64 per cent, nitrogen. 



Calculated for CgHj^NOa = 7-73 per cent, nitrogen. 



The total weight of tyrosine obtained was 0-52 + 0-44 = -96 grm. 



This indicated a percentage of ^a-^a -'^ ^^^ "" ^'^^ °^ tyrosine in the 

 protein. 



