ENERGY SUPPLY OF THE CELL 43 



(CH3)2-CH-CH2-CH(NH2)-C02H + H2O -> 



Leucin 



(CH3)2CH-CH2-CH(OH)-C02H 



i 

 (CH3)2-CH-CH2CH20H + CO2 



Iso-amyl alcohol 



Ehrlich proved this theory by demonstrating that an 

 increase of leucin or isoleucin in the medium caused an 

 increase of fusel oil, while asparagin or ammonium 

 carbonate did not cause such increase. 



In a similar way, Ehrlich (1909) showed that succinic 

 acid is a protein derivative. It is not a reduction product 

 from aspartic acid, however, but derives from glutamic 

 acid by de-amidization and oxidation. 



CH2— CO2H CH2CO2H 



I I 



CH2 CH2 +02-^ 



I I 



CH— CO2H + H2O -^ CH— CO2H 



NH2 OH + NH, 



Glutamic acid Glutamic acid 



CH2— CO2H 



I 

 CH2 



CO2H + CO2 



Succinic acid 



