180 Essays in Biochemistry 



observation that the isotope concentration of the total urea nitrogen 

 of the rats receiving glucose was 30% higher than that of the total 

 urea nitrogen of fasting animals. The experimental results therefore 

 support the view that the nitrogen-sparing effect of carbohydrates is 

 a consequence of the coupling of the oxidation of carbohydrates to the 

 aminophorase-glutamic dehydrogenase system. 



References 



1. H. D. Hoberman, unpublished observations. 



2. H. D. Hoberman and J. Graff, J. Biol. Chem., 186, 373 (1950). 



3. M. Blanchard, D. E. Green, V. Nocito, and S. Ratner, J. Biol. Chem., 155, 

 421 (1944). 



4. S. Ratner, V. Nocito, and D. E. Green, J. Biol. Chem., 152, 119 (1944). 



5. A. E. Braunstein, Advances in Protein Chem., 3, 1 (1947). 



6. P. S. Cammarata and P. P. Cohen, J. Biol. Chem., 187, 439 (1950). 



7. J. A. Olsen and C. B. Anfinsen, J. Biol. Chem., 197, 67 (1952). 



8. H. N. Munro, J. Nutrition, 39, 375 (1949). 



9. M. E. Jones, L. Spector, and F. Lipmann, J. Am. Chem. Soc, 77, 819 (1955). 



10. P. Siekevitz, and V. R. Potter, J. Biol. Chem., 201, 1 (1953). 



11. S. Ratner, Advances in Enzymology, 15, 319 (1954). 



12. P. P. Cohen, and G. L. Hekhuis, J. Biol. Chem., lJfi, 711 (1941). 



13. H. D. Hoberman, J. Biol. Chem., 188, 797 (1951). 



