Pfizer Handbook of Microbial Metabolites 



382 



Beyond historical interest there seems to be little point 

 in attempting to standardize the nomenclature of actino- 

 mycin mixtures. Waksman has proposed that a Roman 

 numeral be assigned to each pure actinomycin, and John- 

 son's group has taken up this practice, actinomycins II 

 and III being distinct from those characterized elsewhere, 

 while IV is identical with Cj or D, etc. Brockmann views 

 this as one more contribution to the confusion of the liter- 

 ature and, claiming the right of discoverer of many of the 

 actinomycins, has made the suggestion that no nomen- 

 clature system will relieve the confusion unless it makes 

 apparent the amino acid sequences of the side-chains. 



Although this does not solve the problem of trivial 

 nomenclature, Brockmann uses a shorthand method of 

 demonstrating the structures of the actinomycins in 



which a symbol < represents the actinocinin moiety, 



the branches at the right symbolizing the amino and 

 quinonoid carbonyl groups. The abbreviated amino 

 acid names are then attached in proper sequence. In 

 most of the asymmetric actinomycins the chains in which 

 the differing amino acids occur have not yet been speci- 

 fied, and this is indicated by an E -symbol, indicating pos- 

 sible reversal of position. 



The structure of actinomycin C3 (which has been 

 synthesized) is given somewhat more fully to show struc- 

 tural details. The custom of arrangement by empirical 

 formula is ignored here to permit grouping by related 

 structures. 



The mitomycins (unclassified) may be actinomycins. 



There is an apparent striking biogenetic similarity 

 among the etamycin, staphylomycin, etc. group of poly- 

 peptides on the one hand and the actinomycins on the 

 other. 



793 Actinomycin C.^ (VII) Cc4H9oOi6N,o 

 235° (dec), [2W -321° ±lo"= 



red crystals, m.p. 232- 



