114 A. I. RINGER 



Prolin is burned in the body, passing through a glucose stage. Three 

 of its carbons are convertible into glucose. (Dakin, 1913 ; Ringer, Frankcl 

 and Jonas.) In all probability, similar to glutaric acid, it passes through 

 a succinic acid stage. It does not give rise to aceton bodies. 



COOH 



CH 2 



> Glucose 



CH 9 



CH/ COOH 



COOH CO 2 



Prolin Succinic Acid 



The fate of oxyprolin has not been worked out definitely. Both prolin 

 and oxyprolin are intimately related to the pyrrol ring 

 CH 



CH' 



which forms the framework of hematin, one of the important derivatives 

 of hemoglobin. Prolin is also found in a number of other coloring sub- 

 stances of the body, like in hair, the skin of dark races, melanins, etc. 

 There can hardly be any question but that the body uses prolin and oxy- 

 prolin in the manufacture of the coloring materials. 



The fate of liistidin in the body is not clear. It does give rise to 

 small amounts of glucose when fed to diabetic dogs and it also causes a 

 slight rise in the acetone bodies formation when perfused through the 

 surviving liver. Neither reaction, however, is definite nor conclusive. 

 We must therefore wait for further research with this substance. Because 

 of its structural relationship to creatinin, the possibility of its being the 

 mother substance of creatinin has been suggested by Abderhalden. 

 CH NH CH 2 N CH 3 



|J _^>CH 



\ 



CH 2 CO 



CHNH 2 



COOH 



Histidin Creatinin 



