An Oxidation Product of Creatine. 145 



could not be taken and thus comparisons of the normal with the 

 tetanic samples were impossible. 



From the comparison in the result it is clear that after guanidine 

 administration the phosphorus is markedly increased, in some 

 cases five times above the normal. The calcium shows no marked 

 change, though there is a tendency for it to decrease as the phos- 

 phate increases. In normal conditions, rabbits with albumin in 

 the urine show a rather higher content of phosphate than those 

 which have no albumin. 



In consideration of the above experiments we may say that 

 the phosphate content of the serum in guanidine tetany is markedly 

 increased, but that the reduction of calcium is rather doubtful. 

 The small number of experiments does not warrant a decision on 

 this important phenomenon. The experiments are being con- 

 tinued and further results will be reported later. 



196 (1374) 



An oxidation product of creatine. 



By L. Baumann and Thorsten Ingvaldsen. 



From the Chemical Research Laboratory, Department of Internal 

 Medicine, State University of Iowa, Iowa City. 



Mercuric acetate in watery solution oxidizes creatine to a- 

 methylguanidoglyoxylic acid (NH 2 .C( :NH).N(CH,)CO.COOH). 

 This compound, which was isolated in pure form, evidently pre- 

 cedes methylguanidine oxalate which was obtained by Dessaignes 1 

 many years ago by heating creatine with mercuric oxide. Dakin 2 

 obtained glyoxylic acid upon oxidizing creatine with hydrogen 

 peroxide. The stages of oxidation of creatine may, therefore, 

 be expressed as follows: 



O 



NH 2 .C(:NH).N(CH 3 ).CH 2 COOH -> NH 2 .C(:NH). 



O 



N(CH 3 ).CHOH.COOH. -> 



H 2 0 



NH 2 .C(:NH).N(CH 3 ).CO.COOH. -> NH 2 C(:NH). 



NH(CH 3 ).COOH.COOH. 



1 Dessaignes, M., Compi. rend. Acad., 1854, XXXVIII, 839. 



2 Dakin, H. D., J. Biol. Chem., 1905-06, I, 271. 



