48 THE PHYSIOLOGY OF PROTEIN METABOLISM 



oxydative deaminization to a keto-acid. 



R 



to 



COOH 



R 



CH . OH hydrolytic deaminization to an oxy-acid. 



COOH 



reductive deaminization to a fatty acid with 



:the same number of 

 OOH carbon atoms. 



Sugar Formation from Amino Acids. 



One problem connected with the disposal of the non-nitrogenous 

 rest which is of considerable interest may be briefly referred to here, 

 namely the production of carbohydrate from this rest Although it is 

 generally supposed that the carbohydrate of the food is mainly con- 

 cerned with the energy needs of the organism it is gradually becoming 

 apparent that carbohydrate is closely concerned with other tissue re- 

 quirements. Lusk (268) has carried out much important work on this 

 subject. He has demonstrated that glycine and alanine are converted 

 into glucose and that three of the carbon atoms contained in aspartic 

 and glutamic acids are also so converted. As regards the sugar produc- 

 tion from meat he has found that fifty-eight parts of glucose may be 

 formed from one hundred parts of meat, and he has further calculated 

 that forty-five per cent, of the total sugar production from protein in 

 diabetes may arise from the four amino acids glycine, alanine, aspartic 

 and glutamic acids. Among other workers who have investigated this 

 problem are Embden and his pupils (113, 114, 115, 116), Glaessner 

 and Pick (156), and Halsey (166). 



