HANDBOOK FOR BIO-CHEMICAL LABORATORY. 41 



Glutamic Acid, C 5 H 9 N0 4 . 

 AMIDO-PYROTARTARIC ACID, C 3 H 6 (NH 2 )(COOH) 2 . 



Preparation. Boil 200 grms. casein (free from fat) with 

 600 c.c. concentrated LLCl and 500 grms. stannous chloride 

 for 3 days in a flask connected with a return condenser. After 

 diluting with 10 vols. water remove the tin by means of H 2 S, 

 and evaporate to syrupy consistency on water-bath. On stand- 

 ing in the cold the syrup will solidify into a mass of crystals; 

 these are stirred up and transferred to a filter connected with 

 a filter-pump, and as much mother-liquor sucked off as possi- 

 ble; then place the moist mass on an unglazed tile and placed 

 in desiccator until dry. Now recrystallize one or two times 

 from as little water as possible with the addition of cone. 

 HC1, and remove the mother-liquor as well as possible. The 

 crystals are now dissolved in a great deal of water and boiled 

 with an excess of lead oxyhydrate until the solution is free 

 from chlorine. Filter, precipitate the lead by H 2 S, filter again, 

 and evaporate the solution to point of crystallization. If these 

 crystals retain still small quantities of chlorine, treat the hot 

 solution with some silver oxide or carbonate; filter, treat the 

 filtrate with H 2 S, filter, and evaporate to crystallization. 



Properties. Glutamic acid crystallizes in the form of 

 small plates or rhombic tetrahedra or octahedra, which are 

 sparingly soluble in cold water, but readily in hot water. It 

 is insoluble in alcohol or ether., and melts at 135-140C. Its 

 dilute HC1 solution has a specific rotatory power of (a) D = -f- 

 31.1 to 31.6. Dilute solutions reduce Fehling's solution. 

 When boiled with Cu(OH) 2 , glutamic acid separates in the 

 form of blue-colored prisms, which are soluble in 3400 parts 

 cold and -400 parts boiling water. 



CH 



Indol, C.H 7 K = C,H 4 CH 



H 



\, 



