134 CHEMISTRY OF THE PROTEIDS CHAP. 



Glycyl-alanin (inactive) : NH 2 . CH 2 . CO . NH . CH(CH 3 ) . COOH. 1 



Leucyl-leucin (inactive) : 



/COOH 

 GlycyU-tyrosin : NH 2 . CH 2 . CO . NH . CH<^ 



X CH 2 .C 6 H 4 .OH. 



Leucyl-/-tyrosin : C 15 H 22 4 N 2 gives Millon's reaction. 



/CO.NH 



Leucin-tyrosin-anhydride : C 4 H 9 CH< ;>CH . CH 2 . C 6 H 4 . OH. 



N NH . C0 / 



2. Tripeptids. The di-glycyl-glycin described above. 



3. Tetrapeptids. Tri-glycyl-glycin : 



NH 2 CH 2 CO . NHCH 2 CO . NHCH 2 CO . NHCH 2 . COOH. 

 a-brom-iso-capronyl-leucyl-glycyl-glycin : 



C 4 H 9 . CHBr . CO . NH . CH(C 4 H 9 ) . CO . NHCH 2 . CO . NHCH 2 . COOH. 

 Dileucyl-glycyl-glycin (inactive) : 

 NH 2 . CH(C 4 H 9 ) . CO . NH . CH(C 4 H 9 ) . CO . NHCH 2 CO . NHCH 2 . COOH. 



4. Pentapeptid. Tetra-glycyl-glycin : 



NH 2 CH 2 CO . NHCH 2 CO . NHCH 2 CO . NHCH 2 .CO . NHCH 2 . COOH. 

 This peptid was prepared from chloracetyl-triglycyl-glycin : 

 C1CH 2 . CO[NH . CH 2 . CO] 3 NH . CH 2 . COOH. 



Derivatives of Pyrrolidin-carboxylic Acid or Prolin (III.) 



The constitutional formula of pyrrolidin-carboxylic acid is given 

 on p. 45. 



Polypeptids, which are derivatives of proline or a-pyrrolidin-car- 

 boxylic acid, have been prepared by E. Fisher and Suzuki. As 

 Willstatter had noticed that a-S-dibrom-valerianic acid is converted 

 into a-pyrrolidin-carboxylic acid, Fischer and Suzuki attempted to join 

 up pyrrolidin-carboxylic acid with other amino-acids by an analogous 

 procedure, and they succeeded with alanin. If the a-8-dibrom-valerianic 

 acid is converted into the chlorinate by means of phosphorus-penta- 

 chloride and is then brought together with an alkaline solution of 

 alanin, there is formed a-S-dibrom-valeryl-alanin : 



CH 2 Br . CH 2 .CH 2 . CHBr . CO . NH . CH(COOH) . CH 3 , 



1 On subjecting fibroin to the combined disintegrating action of hydrochloric acid, of 

 trypsin, and of alkali, E. Fischer and Bergell (" Hydrolysis of Proteids," Karlsbad er 

 Naturforscherversammlung (1902), and in Chemiker Zeitung, 1902, II. p. 939), obtained a 

 crystalline glycyl-alanic, which was, however, not identical with the synthetised product. 



