DECOMPOSITION OF FATTY ACIDS 465 



and aliphatic side chains takes place in much more compli- 

 cated ways which Friedmann and Dakin 34 would outline 

 schematically somewhat as follows : 



R. CH,. CH 8 . COOH 



/ 



R.CH = CH.COOH -[-> R.CO.CH 2 .COOH > R.CO.CH, 



--> 



\ 



R.CH(OH). CH 2 .COOH 



t I 



R.COOH R.COOH. 



If this schema be applied, for illustration, to the indi- 

 vidual case of phenylpropionic acid (C 6 H 5 .CH 2 .CH 2 .COOH) , 

 it will be seen that it can pass into either (by ^-oxida- 

 tion) phenyl-^-oxypropionic acid (B.CH(OH).CH 2 .COOH), 

 or into benzoylacetic acid (C 6 H 5 .CO.CH 2 .COOH) or, finally, 

 into cinnamic acid (C 6 H 5 .CH = CHjCOOH). The last two 

 may then be further catabolized into benzoic acid (C 6 H 5 , 

 COOH). Benzoylacetic acid can by loss of C0 2 pass into 

 acetophenone (C 6 H 5 .CO.CH 3 ), or by reduction into phenyl- 

 /?-oxypropionic acid. 



Transition of this last, shown by the two pairs of arrows, 

 into benzoylacetic acid and cinnamic acid is fully analogous 

 to the previously mentioned equation between /?-oxybutyric 

 acid, diacetic acid and crotonic acid : 



CROTONIC ACID OXYBUTYRIC ACID DIACETIC ACID 



CHg CH=CH COOH ^ CH 3 .CH(OH).CH 2 .COOH ^CH 3 .CO.CH 2 .COOH. 



The catabolism of the fatty acids, therefore, in line with 

 this schema, is not confined to simple oxidation processes ; 

 these latter have associated with them processes of reduc- 

 tion and of water- and C0 2 -cleavage. It may be said in pass- 

 ing that the previously mentioned (p. 385) discoveries of E. 

 Pick and Joannovics as to the conversion in the liver of sa- 



34 E. Friedmann, Med. Klinik, 1911, No. 28; H. D. Dakin, Jour, of Biol. 

 Chem., 9, 123, 1911. 



30 



