Creatin and Creatinin 



LOUIS BAUMAN 



NEW YORK 



Chemistry 



Creatin, methylguanidoacetic acid (CH 3 N CH 2 COOH), was first 

 isolated from meat extract and named by Chevreul in 1835. Twelve 

 years later Liebig isolated it from the muscle of various animals, analyzed 

 it and converted it into its anhydride which he named creatinin. Creatin 

 was synthesized from sarcosin and cyanamid by Volhard (1868), and 

 from sarcosin and guanidin carbonate by Horbaczewski (a) (1885). 



Creatin forms transparent prismatic crystals which contain one mole- 

 cule of water. At room temperature it is soluble in water to the extent 

 of 1.35 per cent. When heated with water or dilute mineral acids it is 

 converted into creatinin. Conversely creatinin is converted into creatin 

 when heated with calcium hydroxid solution. 



CO 



Creatinin ( | ) also occurs in the form of prismatic 



/"ITT -\y C\TT 



Ul 3 lN ^ti2 



crystals which dissolve in water to the extent of 10 per cent; it is also 

 more soluble in alcohol than creatin. Owing to its basic nature it is 

 readily precipitated by the so-called alkaloidal reagents. 



In watery solution creatin is slowly transformed into creatinin, the 

 rate of transformation is slightly less than 0.5 per cent per day at 36 C. 

 Under similar conditions creatinin is changed into creatin so that at the 

 end of 11 months an equilibrium is established in either case. When 

 these substances are dissolved in the urine a similar change takes place 

 (Myers and Fine (fc), 1915). 



Both creatin and creatinin reduce alkaline copper solutions. When 

 boiled with mercuric oxid they are oxidized to methylguanidin and oxalic 



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