604 ISOTOPIC TRACERS AND NUCLEAR RADIATIONS Chap. 30 



N 20 Burris, R. H., and C. E. Miller: Application of N 15 to the study of biological 



nitrogen fixation, Science, 93, 114-115 (1941). 

 N 21 Burris, R. H., and P. W. Wilson: Comparison of the metabolism of ammonia 



and molecular nitrogen in Azotobacter, J. Biol. Chem., 165, 595 (1946). 

 N 22 Burris, R. H., and P. W. Wilson: Characteristics of the nitrogen-fixing enzyme 



system in Nostoc mu'scorum, Botan. Gaz., 108, 254-262 (1946). 

 N 23 Chargaff, E., M. Ziff, and D. Rittenberg: Study of nitrogenous constituents 



of tissue phosphatides, /. Biol. Chem., 144, 343-352 (1942). 

 N 24 Clutton, R. F., R. Schoenheimer, and D. Rittenberg: Studies in protein 



metabolism. XII. The conversion of ornithine into arginine in the mouse, /. Biol. 



Chem., 132, 227-231 (1940). 

 N 25 du Vigneaud, V., M. Cohn, G. B. Brown, O. J. Irish, R. Schoenheimer, and 



D. Rittenberg: A study of the inversion of d-phenylaminobutyric acid and the 



acetylation of /-phenylaminobutyric acid by means of the isotopes of nitrogen and 



hydrogen, /. Biol. Chem., 131, 273-296 (1939). 

 N 26 du Vigneaud, V., S. Simmonds, J. P. Chandler, and M. Cohn: Further investiga- 

 tion of the role of betaine in transmethylation reactions in vivo, /. Biol. Chem., 



165, 639-648 (1946). 

 N 27 Fink, R. M., T. Enns, C. P. Kimball, H. E. Silberstin, W. F. Bale, S. C. Madden, 



and G. H. Whipple: Plasma protein metabolism, normal and associated with shock. 



Observations using protein labeled by heavy nitrogen in lysine, /. Exptl. Med., 



80, 455-475 (1944). 

 N 28 Foster, G. L. : Some amino acid analyses of hemoglobin and /3-lactoglobulin, /. 



Biol. Chem., 159, 431-438 (1945). 

 N 29 Foster, G. L., R. Schoenheimer, and D. Rittenberg: Studies in protein metabo- 

 lism. V. The utilization of ammonia for amino acid and creatine formation in 



animals, /. Biol. Chem., 127, 319-327 (1938). 

 N 30 Graff, S., D. Rittenberg, and G. L. Foster: The glutamic acid of malignant 



tumors, /. Biol. Chem., 133, 745-752 (1940). 

 N 31 Heidelberger, M.: Behavior of antibody protein toward dietary nitrogen in 



active and passive immunity, /. Biol. Chem., 144, 555-562 (1942). 

 N 32 Herbst, R. M., and D. Shemin: The synthesis of peptides by transamination, 



/. Biol. Chem., 147, 541-547 (1943). 

 N 33 Herken, H.: Deut. Gcsundheitsw., 1, 425-432 (1946). 

 N 34 Hevesy, G., K. Linderstr0m-Lang, A. S. Keston, and C. Olsen: Exchange of 



nitrogen atoms in the leaves of the sunflower, Compt. rend. trav. lab. Carlsberg, ser. 



chim., 23, 213-218 (1940). 

 N 35 Jones, H. B.: Preoxygenation and nitrogen elimination. In: Studies on gas 



exchange, U.S. Air Force, Air Materiel Command, Memo. Rept. MCREXD-696- 



114, pp. 7-102, 1948. 

 N 36 Joris, G. G.: The exchange reaction between gaseous and combined nitrogen, 



/. Chem. Phys., 9, 775 (1941). 

 N 37 Kalckar, H. M., and D. Rittenberg: Rejuvenation of muscle adenylic acid 



nitrogen in vivo, studied with isotopic nitrogen, J. Biol. Chem., 170, 455-459 (1947). 

 N 38 Keston, A. S., D. Rittenberg, and R. Schoenheimer: Studies in protein metabo- 

 lism. IV. The stability of nitrogen in organic compounds, /. Biol. Chem., 127, 



315-318 (1939). 

 N 39 Keston, A. S., S. Udenfriend, and R. K. Cannan: Microanalysis of mixtures 



(amino acids) in the form of isotopic derivatives, /. Am. Chem. Soc, 68, 1390 (1946). 

 N 40 Kritsman, M. G., and A. S. Konikova: Primenenie tiazhelykh izotopov vodoroda 



