Pfizer Handbook of Microbial Metabolites 



302 



In this case the broth was hydrolyzed and compared with the 

 original to eUminate interference by small peptides in the mi- 

 crobial assays. Tryptophan and methionine were destroyed by 

 the hydrolysis and chromatography procedure and are absent 

 from the second part of the table. It was found that 53% of 

 the extracellular organic nitrogen was represented by free amino 

 acids. Some strains of Ustilago maydis produce 200—300 jxg. 

 of lysine per milliliter." 



A study of the extracellular nitrogen of several molds' gave 

 the results in the accompanying table. 



TABLE ill 

 Amounf of Nitrogen Assitnilafed Which Appeared in fhe Medium After Seven Days Growth 



The extracellular nitrogen was related to the nitrogen supplied 

 in two cases: 



TABLE IV 

 Formation of Extracellular Nitrogen in Relation to Initially Added Nitrogen Which 



Disappeared 



M. Richards and R. H. Haskins, Can. J. Microbiol. 3 543 (1957). 

 A. G. Morton and D. Broadbent, 7. Gen. Microbiol. 12 248 (1955). 



