E. W. YEMM 



Virtanen, A. I. and Rautenen, N. (1952). Nitrogen Assimilation. The Enzymes 

 Vol II, Pt. 2, edited by Sumner and Myrbach. Academic Press, New York. 



Willis, A.J. (1950). Nitrogen assimilation and respiration in barley. Ph.D. Thesis: Uni- 

 versity of Bristol. 



Willis, A.J. (1951). Synthesis of amino-acids in young roots of barley. Biochem.J. 49, 

 xxvii. 



Waelsch, H. (1952). Certain aspects of intermediary metabolism of glutamine, 

 asparagine and glutathione. Advances in Enzymology 13, 237. 



Woodford, E. K. and Gregory, F. G. (1948). Preliminary results obtained with 

 an apparatus for the study of salt uptake and root respiration of whole plants. 

 Ann. Bot., Lond. N.S. 12, 335. 



Yemm, E. W. (1937). Respiration of barley plants. III. Protein catabolism in starving 

 leaves. Proc. Roy. Soc. B 123, 243. 



Yemm, E. W. (1949). Glutamine in the metabolism of barley plants. Mew Phytol. 48, 



3i5- 

 Yemm, E. W. (1950). Respiration of barley plants. IV. Protein catabolism and the 



formation of amides in starving leaves. Proc. Roy. Soc. B 136, 632. 



Yemm, E. W. and Folkes, B. F. (1954). The regulation of respiration during the 



assimilation of nitrogen in Torulopsis utilis. Biochem. J. 57, 495. 



Discussion 

 Chairman: J. Bracket 



G. Pontecorvo. Your results on transamination of glutamic acid to form other amino- 

 acids in the heirarchic order shown are exactly the same as those found by Fincham 

 and others by the less orthodox but more efficient method of using mutants in micro- 

 organisms. This supports your conclusion as to the general occurrence of such pro- 

 cesses. 



E. W. Yemm. The investigation of transamination in barley embryos is not yet com- 

 plete. The relative activities given are based on comparative measurements in cell- 

 free preparations without addition of pyridoxal phosphate. From the work of Cohen 

 it seems possible that other transaminations may be detectable after reinforcement 

 of the preparations by addition of the coenzyme. 



W. S. Reith. It is very interesting to see this striking difference in the relative amounts 

 of glutamine and asparagine. We have found in the growing cells of bean roots just 

 the opposite situation. There the amount of asparagine greatly exceeds that of gluta- 

 mine. We interpreted this as an accumulation of asparagine while the glutamine was 

 rapidly depleted owing to its active participation in transaminations. 



As for protein-nitrogen determinations, I should like to point out that we find that 

 very misleading results can be obtained from trichloracetic acid precipitates. Such 

 protein precipitates can contain a great amount of non-protein nitrogen. 



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