132 ASYMMETRY OF PROTOPLASM A^D CANCER 



possibility can be checked. Lipniaiiii reports that most of 

 his hj^drolyses were carried out in HCl containing* heavy 

 water. Subsequent determinations of the content of deu- 

 terium attached to the alpha carbon atom of glutamic 

 acid w^ill show, according to the suggestion of du Vig- 

 neaud whether or not the partial racemization is due to 

 the process of hydrolysis. 



If the recent data of Waldschmidt-Leitz and Mayer 

 (1939) are confirmed, they will undoubtedly lead to new 

 developments in the study of the problem of cancer from 

 the viewpoint of protoplasmic asymmetry. According 

 to Waldschmidt-Leitz, if unusual optical isomers of some 

 amino acids really enter into the composition of malignant 

 cells, there should be specific proteolytic enzymes to cat- 

 alyze the spatially unusual metabolic processes. It is 

 known that peptidases of healthy animal tissues do not 

 split up such polypeptides which consist of unusual optic 

 isomers of amino acids. Waldschmidt-Leitz showed this 

 to be true also of the aminopoly peptidase and the dipep- 

 tidase from the serum of healthy persons. But the prop- 

 erties of peptidases from the serum of cancer patients are 

 radically diiferent, they can split up polypeptides con- 

 sisting of unusual optic isomers. This feature was used 

 by Waldschmidt-Leitz in his diagnosis method. 



One can hope that more light be shed on this important 

 problem in the near future. 



BIBLIOGRAPHY 



ARNOW, E. and J. OPSAHL, Science, 90, 257, 1939. 

 BAYBRLE, H., Biochem. Z., 303, 251, 1939. 

 CHIBNALL, A., Nature, 14',, 71, 1939. 

 EWING, J., Science, 87, 399, 1938. 

 GRAFF, S., J. Biol. Cheni.. 130, 13, 1939. 



KoGL, F. and H. ERXLEBEN, Z. physiol. Chem., 258, 57; 2G1, 154; 

 Naturiviss, 27, 486; Nature, 1. ',.',, Ill; Z. Krehsforsch., J,9, 291, 1939. 



and A. AKKERMAN, Z. physiol. Chem., 262, 



141, 1939. 

 LIPMANN, F. et at., Science, 01, 21, 1940. 



WALDSCHMIDT-LEITZ. E. and K. MAYER, Z. physiol. Chem., 262, IV 

 1939. 



WARBURG, O., Uber den Stoffwechsel der Tumoren. Berlin. 1926. 



