222 THE ANTIBIOTICS 



Reference: Charney, J., Roberts, W. S., and Fisher, W. P., Antibiotics & 

 Chemotherapy, 2, 1952, 307-309; Fisher, W. P., and Charney, J., 

 ibid., 311-314. 



Proactinomycins A, B, C 



Produced by: Nocardia gardneri. 



Method of extraction: Broth pH adjusted to 10, extracted with amyl acetate. 

 Back extracted with acetate buffer at pH 4. pH adjusted to 10, ex- 

 tracted with amyl acetate. Back extraction with acid water (pH 4, 

 HC1). Concentration and lyophilization. 



Chemical and physical properties: Basic substance. Stable at pH 2 to 8. 

 Slightly soluble in water at neutrality. Soluble in alcohol, acetone, 

 ether, chloroform, and benzene. This substance can be resolved by 

 countercurrent distribution into three antibiotics: 

 Proactinomycin A: C27H47NO8, m.p. 168-169°C 

 Proactinomycin B: C28H49NO8, m.p. 83-87°C 

 Proactinomycin C: C24H 4 iN0 6 



Biological activity: Active against gram-positive bacteria. Very limited 

 activity against gram-negative bacteria. A and C have about the same 

 activity. B is less active on a weight basis. The three substances have 

 identical qualitative antibacterial spectra. Proactinomycin A offers 

 little protection to mice infected with Streptococcus pneumoniae. 



Toxicity: LD 6 o (mice), intravenous, 90 mg/kg (crude proactinomycin); 

 150 mg/kg (A) ; 120 mg/kg (B) ; 80 mg/kg (C). 



Utilization: None. 



Reference: Gardner, A. D., and Chain, E., Brit. J. Exptl. Pathol., 23, 1952, 

 120-127; Marston, R. Q., ibid., 30, 1949, 398-407; Marston, R. Q., 

 and Florey, H. W., ibid., 407-418. 



Puromycin 



Produced by: Streptomyces alboniger. 



Synonym: Achromycin. 



Method of extraction: Not published. 



Chemical and physical properties: Nonpigmented basic substance, with 

 dimethylaminopurine, O-methyl-L-tyrosine and 3-amino-D-ribose 

 groups, m.p. 175.5-177°C. Characteristic infrared absorption. [a]l 5 

 — 11° in ethanol. Maximum light absorption at 275 m/i in O.liV NaOH. 

 C 22 H 29 N 7 5 . 



Biological activity: Inhibits largely gram-positive bacteria Sarcina lutea, 

 Micrococcus pyogenes var. aureus, Bacillus subtilis, Klebsiella pneu- 

 moniae (2-8 mcg/ml); limited activity against Escherichia coli, Pro- 



