ALBUMINS OR PROTEINS. 239 



ent from the comparatively large production of lactic acid. The latter 

 may be derived from various sources. Here, the carbohydrates, as well as 

 the amino acids, come into consideration. We know some of these which 

 are closely related to lactic acid. We would refer especially to alanine: 



CH 2 . SH 



CH . NH 2 



COOH 

 Cysteine 



We can also imagine that serine and cysteine may bear some relation to 

 the formation of lactic acid. Leucine might also produce lactic acid, if we 

 assume that its carbon chain is broken in the middle: 



3 ,CH 3 

 ^CR 



CH 2 

 H . NH 2 > Alanine 



COOH 



Leucine 



We can, therefore, easily derive all of the components of uric acid 

 direct from albumin. It is not to be implied, however, that lactic acid 

 may not also arise from other sources. 



It might be thought that some idea of the formation of urea could be 

 obtained from the way uric acid is produced. We, however, know that 

 there are several ways in which the uric acid formation may be explained. 

 We can take all of our theories for the formation of urea and apply them 

 directly to that of uric acid. It is possible that the synthesis in this case 

 is primarily carried out with the elimination of water; although it is also 

 conceivable that an oxidation synthesis may be a factor. It is not at all 

 impossible that the formation of urea may play a part in the synthesis of 

 uric acid. 



Wiener's investigations will give us an idea of these relations. He 

 found that tartronic acid: 



C 



HOH 



COOH 

 and its ureide (dialuric acid) : 



NH CO 



CO CHOH 

 NH CO 



