NITROGEN METABOLISM 239 



(h) liotb enantiomorphs are attacked at the same rate, 

 giving an inactive residue, and (c) the rates are different 

 but not very widely so, resulting in an optically active 

 but impure mixture of the acids. The method can be 

 used as a means of resolution of the isomers, but has the 

 disadvantage of giving a maximum possible yield of 50 

 per cent, and of destroying the naturally occurring isomer. 

 The problem of protein synthesis by micro-organisms 

 will be considered in Chapter XVIII, 



For further reading : — 



E. F. Gale, " Enzymes Concerned in the Primary Utilisation of Amino 

 Acids by Bacteria." Bad. Reviews, 4 (1940), 135. 



P. Hirsch, " Einwirkmig von Mikro-organismen auf die Eiweisskorper." 

 Die Biochemie in Einzelldarstellmigen. IV. 



H. Raistrick, Papers in Biochem. J., 11 (1917), 71; 13 (1919), 446; 15 

 (1921), 76. 



M. Stephenson, " Bacterial Metabolism," Chapter V. 2nd Edition. 

 Longmans, Green & Co. London, 1939. 



