DECOMPOSITION OF PROTEINS 485 



active amino acids, both forms are attacked, at equal or unequal rates. 

 In the case of glutamic acid, the rate is the same. 37 



The amides are also readily broken down by various microorganisms, 

 especially in the presence of available energy. Bad. vulgare will almost 

 completely hydrolyze asparagine to ammonia and aspartic acid in 

 twenty-four hours. The acid is changed, at the same time, to succinic 

 acid, or acetic acid and ammonia. Bad. pyocyaneum 3 * attacks readily 

 aliphatic and cyclic amino acids as sources of energy, but not benzene 

 derivatives (p- or m — amino-benzene) . It decomposes tyrosine com- 

 pletely; tryptophane is broken down to (NH 4 ) 2 C0 3 and indol; the 

 indol is converted to anthranilic acid. In the decomposition of amino 

 acids by Bad. pyocyaneum, the carboxyl group is first removed and 

 ammonia is then formed. 39 



Decomposition of organic nitrogenous compounds of a non-protein 

 nature. In addition to proteins, other organic nitrogen compounds, 

 like lecithine, methylated amines, purine bases and other substances 

 present in plant or animal tissues and found in the soil 40 are acted upon 

 by microorganisms with the formation of simpler compounds; ammonia 

 is one of these. 



Lecithine is first split to choline, glycerophosphoric acid and fatty 

 acids: 

 CH 2 -OR 

 CH-ORi CH 2 OH 



CH 2 -OPo/ /(CH 3 ) 3 + 3H 2 = CHOH 



X 0-(CH 2 ) 2 -N< | /OH 



x OH CH 2 0-PO< + ROH + R 1 OH + 



X)H 

 Glycerophospho- Fatty acids 

 ric acid 



(CH 3 ) 3 



(CH 2 ) 2 OH.n/ 



Ndh 



Choline 



37 Neuberg, C. Verhalten von racemischer GlutaminsaAire bei der Fiiulins. 

 Biochem. Ztschr., 18: 431^34. 1909. 



38 Supniewski, J. Der Stoffwechsel der zyklischen Verbindungen bei Bacillm 

 pyocyaneus. Biochem. Ztschr., 146: 522-535. 1924; Compt. Rend. Acad. Sci. 

 Biol., 89: 1379. 1923. 



30 Further information on bacterial decomposition of amino acids is given by 

 Brasch, W. tJber den bakteriellen Abbau primarer Eiweiszspaltprodukte. Bio- 

 chem. Ztschr., 18: 380-390. 1909; 22: 403. 1909; Ackermann, D. tlber die 

 Entstehung von Faulnisbasen. Ztschr. physiol. Chem., 60: 482-501. 1909; 65: 

 504-510. 1910; Ellinger, A. Uber die Entstehung von Faulnisbasen. Ztschr. 

 physiol. Chem., 65: 394-396. 1910. 



40 Potter, R. S., and Snyder, R. S. Soluble non-protein nitrogen of the soil. 

 Jour. Agr. Res., 6: 61-65. 1916; Lathrop, 1917 (p. 474). 



