130 ASYMMETRY OF PROTOPLASM AND CANCER 



chemical behaviour. These enzymes are absent from the 

 sermn of healthy persons. 



Kogl and Erxlebeu also isolated several other amino 

 acids from proteins of normal and malignant tissues and 

 measured their optical rotatory power. Serine and pro- 

 line, which undergo easily a partial racemization in hy- 

 drolysis, were' obtained as partially racemic products in 

 healthy tissues. Proline instead of specific rotation 

 aa = ~ 84.9° gave a value of « = - 82.4°, and serine, in- 

 stead of a = H- 14.45°, gave a = + 8.38°. But such amino 

 acids as valine, leucine and glutamic acid were practically 

 optically pure when isolated from healthy tissues, while 

 partially racemic preparations were isolated from malig- 

 nant tissues (Table 1). 



TABLE 1 



Rotatory Powek of Some Amino Acids Lsolated from Ovarial 



Carcinomes. 



• (Kogl and Erxleben, 1939.) 



In the case of glutamic acid, racemization is most evi- 

 dent, since as far as 42.7% consists of the unusual d(-) 

 form. Such observations have led Kogl and Erxleben to 

 conclude that the unusual optical isomers of some amino 

 acids participate in the composition of cancer cells. The 

 latter would, then, be characterized by some particular 

 spatial molecular configuration, on account of which the 

 growth-controlling enzymes would be disturbed. 



According to Kogl and Erxleben, partial racemization 

 of glutamic acid in cancer tissues is most evident and it 

 could be checked easily. This observation has been se- 

 verely criticized by Chibnall (1939) and also by Graff 

 (1939) who reported to have isolated only optically pure 



