Pfizer Handbook of Microbial Metabolites 470 



(6) Birch (1958),^ Mothes, et aZ. (1958):" 

 C 



Isoprene 

 Equiva- " 

 lent 



C=C 



c 



\ 



c 



NHCH31 



"-N 



J 



Tryptamine — > — > — > Lysergic Acid 

 Equivalent 



Each of these hypotheses has had its votaries, but now 

 experimental work is beginning to accumulate. There 

 have been conflicting results, partly because some experi- 

 menters have injected labeled precursors into infected rye 

 plants, while others added them to cultures grown on arti- 

 ficial medium. 



The 5-hydroxytryptophan proposals have been criti- 

 cized^ because no 5-hydroxyindole analogues of lysergic 

 acid have been found in nature, and because (obviously 

 the devices of organic chemists) they suffer from some 

 rather improbable biological intermediates. Brady has 

 found that in artificial culture tryptophan was an efficient 

 precursor for the clavine alkaloids, while 5-hydroxytrypto- 

 phan was not.^^ 



By using parasitic cultures one group reported good in- 

 corporation of /;j-C^*-tryptophan,^" while another reported^- 

 only weak labeling of the alkaloids isolated from the 

 sclerotia. 



By use of a cell homogenate technique, it was found 

 that alanine and phenylalanine were incorporated into 

 ergotamine and the ergotoxine complex, but not into 

 ergonovine, which suggests that these amino acids are 

 precursors of the peptide structure of the water-insoluble 



^ G. E. Wolstenholme and Cecilia M. O'Connor, CIBA Foundation 

 Symposium on "Amino Acids and Peptides with Antimetabolic Ac- 

 tivity," A. J. Birch and Herchel Smith, Oxidative formation of bio- 

 logically active compounds from peptides, Little, Brown and Co., Bos- 

 ton, 1958, pp. 254-256. 



'^' K. Mothes, F. Weygand, D. Groger and H. Grisebach, Z. Natur- 

 forsch. i;}b 41 (1958). 



" Lynn Robert Brady, Dissertation Abstr. 20 2526 (1960). 



'^ R. J. Suhadolnik, L. M. Henderson, J. B. Hanson and Y. H. Loo, 

 ;. Am. Chem. Soc. 80 3153 (1958). 



