Pfizer Handbook of Microbial Metabolites 436 



true in heme synthesis (in rats)."* The biosynthesis at 

 least seems to be related to the metabolism of 5-carbon 

 units such as proUne, ornithine and glutamic acid. It 

 was further proposed^ that the methoxyl group in one pyr- 

 role ring indicated derivation from hydroxyproHne, and 

 that the colorless Cjo pyrrolic substance, which is thought 

 to be a prodigiosin precursor/' was also probably derived 

 from two C-5 units and that the w-amyl side-chain also 

 might be a rudimentary C-5 amino acid chain. In this 

 connection, the isolation of a C25 "prodigiosin-like pig- 

 ment"' from a streptomycete should be mentioned. While 

 all of the proposals made are not entirely compatible with 

 the revised structure published since,^ the basic tenets 

 seem to be sound. 



Orange and blue variants of prodigiosin occur. The 

 latter, which are less soluble, may be metal chelates. 



Some work also has been done on the biosynthesis of 

 the pyrrolic pigments of Bacillus bruntzii, and glycylgly- 

 cine was found to be a better precursor than glycine and 

 a number of other peptides.^ 



It is safe to say that natural pyrroles are formed by a 

 variety of methods. Demonstration of the participation 

 of erythrose in the shikimic acid biosynthetic route has 

 inspired the admonition that erythrose and its 4-C-atom 

 derivatives should not be ignored as possible precursors 

 of furans and pyrroles.^" 



Because of their importance in photosynthesis, in he- 

 moglobin, in cytochromes and peroxidases and in the 

 chromophore of vitamin B12, there has been much investi- 

 gation of the general mode of biosynthesis of porphyrins. 

 It is likely that a similar method is operative in all cases. 



Porphyrins are present in yeasts, molds and bacteria. 



= David Sherain and D. Rittenberg, J. Biol. Chem. 166 621 (1946). 



^ Ursula V. Santer and Henry J. Vogel, Biochim. et Biophys. Acta 

 19 578 (1956). 



^ F. Arcamone, A. DiMarco, M. Ghione and T. Scottl, Giom. 

 microbiol. 4 77 (1957). 



^ Harry H. Wasserman, James A. McKeon, Lewis Smith and Peter 

 Forgione, J. Am. Chem. Soc. 82 506 (1960). 



^ J. G. Marchal and S. Baldo, Trav. lab. microbiol. fac. pharm. 

 (Nancy) No. 18 187 (1956). 



'"Ernest Wenkert, Experientia 15 166 (1959). 



