140 



WALTER JONES 



H0\ 

 0-P O . C B H 8 3 . C 4 H 3 N 2 2 



HO/ 



Uracil Nucleotide (Levene (d), 1919) 



They are crystalline dibasic acids which closely resemble phosphoric acic 

 in their acidic conduct. They form crystalline dibrucine salts which diffe 

 from one another in their solubilities, thus making possible the purificatioi 

 of the nucleotides and their separation from one another. 



The two purine nucleotides easily undergo acid hydrolysis, giving ris 

 to phosphoric acid pentose and purine base: but the pyrimidine nucleotide 

 are very stable, and must be treated severely before hydrolysis is effect* 

 This explains the conduct of nucleic acid toward hydrolytic agents. 



It will be seen that a thermostable physiological agent (a ferment?' 

 is present in the pancreas, which at the body temperature causes a decor 

 position of yeast nucleic acid into its four component nucleotides. 



The Nucleotide Linkages of Yeast Nucleic Acid. It has been pointe 

 out that the work of the earliest investigators indicated the nucleotide 

 structure of yeast nucleic acid. But this work gave no suggestion of 

 points where the four nucleotides are united to one another in yeast nucle 

 acid, or in other words, the location of the nucleotide linkages. The loc 

 tion was later assumed, without any evidence, to be through the phosphoric 

 acid groups, but this assumption is not correct. The nucleotide linkag 

 involve neither the phosphoric acid groups, nor piurine groups, and prol 

 ably not the pyrimidine groups. This conclusion is based principally upoi 

 the following. 



I. The conversion of yeast nucleic acid into simpler nucleotides 

 not attended by an increase in acidity. (Jones (e), 1920.) There woulc 

 be a marked increase in acidity if the nucleotide linkages involved 

 phosphoric acid groups. 



II. The laws governing the liberation of phosphoric acid from thi 

 nucleotides are the same, whether the nucleotides are free or combined 

 nucleic acid. The same is true for the purines, and also for the pyrii 

 idines, so far as experiments with the latter are possible. (Jones (c 

 1920.) 



If the nucleotide linkages involve neither the phosphoric acid gr 

 the purine groups nor the pyrimidine groups, they can only involve the 

 carbohydrate groups. Nucleic acid should therefore probably have the 

 following formula which represents the substances as a polysaccharide. 



[ It should be noted that this formula is arrived at by exclusion and it 

 intended primarily to indicate the points at which the'nucleotide linka^ 

 do not exist. 



