ORIGIN OF GREATEST FROM ARGININ 131 



hypothesis is as far from proof as the other. Experiments 

 on the excised living uterus have, however, constantly indi- 

 cated that the amount of creatin, in proportion to the weight 

 of the uterine muscle, increases with the muscular activity 

 which has been in play. 36 



Possible Origin of Creatin from Arginin. It must be 

 confessed at the last that we really do not know the ultimate 

 derivation of creatin. Apparently it originates from 

 protein. Even if we actually had proved to our satisfaction 

 that it is formed in the course of tissue autolysis, this would 

 not prove, however, that it necessarily originates from the 

 proteins. Other tissue components, known and unknown, 

 might, with equal propriety, enter into question. If, how- 

 ever, the graphic formula of creatin is examined and 

 compared with that of arginin, 



CREATIN ARGININ 



/NH 2 ,NH 2 



C(NH)< C(NH)< 



\ \ 



CH 2 .COOH CH 2 



CH 2 



CH 2 



CH.NH, 



COOH, 



our biochemical sense suggests (it must be confessed that 

 even with the best of intentions we cannot get on without 

 something of the sort) that a relation between the substances, 

 even if not proved, is, a priori, extremely probable. From 

 arginin, which forms one of the important constituents of 

 the protein molecule, by a typical oxidation there may be 



/ / NHz 

 produced guanidin acetic acid ( ( } \NH-CH 2 Y which re- 



cooir 

 quires only a simple methyl binding for transformation into 



86 Rubsamen and Gusikoff (E. Kehrer's Clinic, Berne), Arch. f. Gynakol., 

 95, 461, 1912. 



