a. Williams 205 



A very similar result was obtained basing the calculation on the 

 content of nitrogen. 



0-1181 grm. gave NHg equal to 9-5 c.c. N/10 acid 



= 0-0133 grm. N = 1126 per cent. N. 

 11-26-10-69 ,._ -57 .__ . . „ 4. f V a 



11-97 - 10- 69 ^ ^ r28 ^ "" P^^ ^ vahne and 



55-5 per cent, of leucine. 



The weight of dry acids left for the separation was 21-70 grms. The 

 finely powdered acids were completely dissolved in 152 c.c. of water 

 and 32 c.c. of concentrated ammonia. 48-6 c.c. of lead acetate solution 

 (1-1 m.) were then added carefully from a burette. The precipitate 

 was washed in the usual way. 21-17 grms. of dry lead salts were 

 obtained and then analysed. 



0-2467 grm. gave 0-1623 grm. PbS04 - 0-1108 gr. Pb = 4491 per cent. Ph. 

 0-2933 grm. gave 0-1925 grm. PbS04 = 0-1314 gr. Pb = 44-82 per cent. Ph. 



Mean of duphcates is 44-86 per cent. Ph. 



Calculated for Pb (C6Hi202N)2 44-29 per cent. Ph. 



The content of lead in this preparation is too high, showing the 



presence of lead vahne with the lead leucine to the extent of 20 per cent. 



Lead vahne contains 47-14 per cent, of lead. 



44-86 - 44-29 ^ jqq ^ -57 ^^ ^^^ _ ^q o/ i^ad valine, 80 % lead leucine. 

 47-14 — 44*29 2-85 



It follows then that the 21-17 grms. of lead salts obtained were 

 made up of 4-23 grms. lead vahne and 16-94 grms. lead leucine. This 

 weight of lead leucine is equal to 9-51 grms. of free leucine, which 

 becomes 9-98 grms. upon allowing for portions removed for analysis. 

 Adding to this the 15-98 grms. of leucine obtained in the previous 

 separation (see page 200) the total weight comes to 25-96 grms., which 

 corresponds to a percentage of 9-01 of leucine isomers in the protein. 



The vahne indicated by the alanine- vahne separation was 16-13 grms. 

 (see page 203). 



The 21-70 grms. of mixture upon which the second lead separa- 

 tion was carried out contained 21-70- 9-51 = 12-19 grms. of vahne. 

 After allowing for material removed for numerous carbon and 

 nitrogen determinations, this is equal to 12-55 grms., making a total 

 of 16-13 + 12-55 = 28-68 grms. of vahne in the protein. 



The total weight of the dry acids of Fractions 1 and 2 after extraction 

 of prohne was 56-7 4- 10-8 = 67-5 grms. From this 25-96 grms. of 

 leucine, 10-29 grms. of alanine, and 0-764 grm. of glycine have been 



14—2 



