CHEMICAL NATURE OF ANTIBIOTICS 



63 



NHa— C— NHCH.— C— NH 

 NH NH 



N' 



I 

 CH3 



netrop.sin 



i'— CONH- 



^N 

 CH, 



-CONHCH.CH., 



I 

 CO 



I 



NH2 



Two of these substances stand apart ciii, neocide, matamycin, amphomycin, 



because their molecules contain a metal, cinnamycin, bryamycin, and thiostrepton. 

 These are the iron-containing grisein and In Part B of this book, a table lists the 



the copper-containing phleomycin. amino acids identified in the hydrolysates 



Grisein and albomycin are mixtures of of antibiotics of actinomycetes and the 



components. Hydrolysates of crude grisein antibiotic or antibiotics in which the acids 



and albomycin contain many amino acids. 

 Pvu'er preparations of grisein contain only 

 glutamic acid and an unidentified amino 

 acid, whereas a purified preparation of one 



have been fovuid. 



Proteins 



The most chemically complex antibiotics 



of the albomycins contains only ornithine are protein or i)rotein-like sul)stances, such 



and serine. Removal of iron from Ili(> grisein 

 molecule results in a loss of the yellow- 

 orange color of the compoimd and in a re- 

 duclion in its l)iol()gical activity against 

 gram-positive and gram-negative bacteria. 

 I'lilcomi/cin contains copper and is prob- 



as actinomi/aiin, A'arious hactcriolijlic factors, 

 ccphalomi/cin, and micromonosporin. 



As this brief survey of what is known of 

 the chemical structure of antibiotics of 

 actinomycetes has shown, these filamentous 

 l)acteria have the abifity to produce some 



at)ly formed of two moieties, a polypeptide intriguing compounds. The elucidation of 

 and a cart)ohydrate. This cobalt-blue com- the exact structure of an antibiotic, in com- 

 pound, which is active against liacteria and plete stereochemical detail, is a type of work 

 mycol)acteria, loses color upon remox'al of the which her(>tofor(> has been mainly of aca- 

 metal, with a concomitant slight I'edudion demic interest. However, eventually a firmer 

 in antimycobacterial activity. link will l)e made between structure and 

 Numerous other polypc^ptides are pro- mode of action, and chemotherapy will be- 

 duced by actinomycetes, such as phalaniy- come a completely rational discipline. 



