ARGININ. 439 



!.NH C.NH 



rH.CH,.CHrCH,.COOH + O, = NH, + C00H.CH,.CH,.C0OH. 



GVASi^TS. Sncdsic Acid. 



The demonstration of the formation of succinic acid from ai^inin 

 explains the presence of this acid in fermentation and putrefaction. 

 Indeed it will be seen that the study of the cleavage products of 

 proteids and more directly of arginin have given us an entirely dif- 

 ferent view of the origin of urea, guanidin, putrescin and of suc- 

 cinic and amido valerianic acids, whether formed within the body, 

 or by the action of bacteria or of chemicals on proteids outside of 

 the body. 



Arginin exists in both the active and inactive form. According 

 to Kutscher* all proteids except fibrin yield the dextro-rotatory 

 base. It should be noted in this connection that fibrin is the only 

 proteid examined which has been submitted to tryptic digestion ; all 

 others have been hydrolyzed by acids and it is quite probable that if 

 treated with trypsin they will also yield inactive arginin. More- 

 over, auto-digestion of the pancreas, if short in duration, may yield 

 also the inactive form. From Balke's antipepton obtained by the 

 pancreatic digestion of fibrin he isolated both forms whereas in auto- 

 digestion of the pancreas only the active arginin was found. It 

 would seem from this as if the fibrin either contained only inactive 

 arginin or else it contains a levo-form which racemizes with the 

 dextro-arginin derived from the pancreas proper. The dextro- 

 arginin on heating with sulphuric acid, and its nitrate when ex- 

 posed to dry-heat of 210°, yields the inactive form. On account of 

 slight differences Gulewitsch believed that the arginin derived from 

 plants was distinct from that of animal proteids but this view has 

 been shown by Schulze ^ to be incorrect. The active and inactive 

 arginins are the only two kinds known at present. 



The free base can be prepared from the acid arginin silver nitrate 

 by changing this to arginin silver which in turn can be decomposed 

 with hydrogen sulphid. It crystallizes in rosette-like masses of 

 plates or thin prisms which melt at 207-207.5° (corr.). It is odor- 

 less but has a slightly bitter taste ; is strongly alkaline and takes 

 up carbonic acid. From solutions of the salts of heavy metals it 

 precipitates the oxids and from ammonium salts it liberates ammo- 

 nia. It is easily soluble in water but is almost insoluble in boiling 

 alcohol. Like ammonium salts and amido compounds it takes up 

 iodin and yields iodic acid. (Schmidt, Z. P. C, 34, 64.) Sodium 



> ZeiU. physiol. Chem., 32, 476 ; 26, 114 ; 28, 90. 

 sZeife. phyml. Chem., 27, 178, 368 ; 29, 329. 



