435 Pyrroles, Porphyrins and Related Compounds 



NH.. 

 HOOC— CH— CH, O 



S C CH -NHo(COCH3) 



S C CO 



H 



III 



/\ 



S C CH— NH—CO—CH:, 



111 

 CH C C=0 + Serine or Alanine 



\ / 



H 



Holomycin 



A glycylcystine intermediate I is reminiscent of the pep- 

 tide intermediate now implicated in the biosynthesis of 

 penicillin.^ It is known that there has been some aca- 

 demic interest in the origin of these compounds, however, 

 and since no publications have been forthcoming, perhaps 

 the problem is more complicated. 



Pyoluteorin, with a carbonyl group at the two position 

 of the pyrrole moiety, suggests an origin in the glutamate 

 -^ prohne pathway, perhaps from 8^-pyrroline-5-carbox- 

 ylic acid, although the chlorination of the ring may indi- 

 cate a less obvious derivation. The pyrrohdine moiety of 

 the plant alkaloid, nicotine, has been shown to be bio- 

 synthesized from glutamate.- 



The origins of prodigiosin and netropsin are not obvious. 

 Some work has been done on prodigiosin.^ * Glycine-2-C^* 

 was incorporated into prodigiosin, but 5-aminolevulinic 

 acid-5-C^* was not.* This apparently distinguishes 

 the method of biosynthesis from that of the por- 

 phyrins. Moreover, C^ '-labeled L-proline was found to be 

 several times more efficient as a prodigiosin precursor in 

 Serratia marcescens than glycine, while the reverse is 



^ H. R. V. Arnstein, D. Morris and E. Toms, Biochim. et Biophys. 

 Acta 35 561 (1959). 



- Thomas Griffith, Kenneth P. Hellman and Richard U. Byerrum, 

 J. Biol. Chem. 235 800 (1960). 



3R. Hubbard and C. Rimlngton, Biochem. J. 46 220 (1950). 



^ Gerald S. Marks and Lawrence Bogorad, Proc. Nat. Acad. Sci. 46 

 25 (1960). 



