3()8 



DESCRIPTIONS OF ANTIBIOTICS 



omycin believed to be the same as mikamycin (4). 

 Related to streptogramin and antibiotics PA 114 A 

 and B (2). Mi is identical with PA 114A and E 

 129A. Component S differs from E 129B and PA 

 114B (6). 



Method of extraction: Broth-filtrate extracted 

 with chloroform. Extract concentrated. Inactive 

 precipitate formed on addition of petroleum ether; 

 precipitate discarded. Petroleum ether concen- 

 trated and residue dissolved in aqueous methanol. 

 On acidification to pH 3.0 with HCl, the antibiotic 

 precipitates (1). Separation into components Mi 

 and Mil , and S by chromatographing a chloro- 

 form-benzene (1:1) solution of the crude anti- 

 biotic on silica gel. Development with chloroform 

 gives five zones: (1) narrow brown, (2) broad 

 yellow, (3) narrow brown, (4) broad tan, and (5) 

 dark brown. Fractions containing zones 1, 2, and 

 3 are dissolved in hot methanol to give crystals of 

 component S. Fractions containing the first half 

 of zone 4 are dissolved in hot acetone. Component 

 Mi precipitates on addition of petroleum ether; 

 recrystallized from acetone or ethanol-water. 

 Component Mn is contained in fractions fron\zone 

 5 and the last half of zone 4, along with Mi and 

 pigmented impurities; Mn was not purified. 



Cheuncal and physical properties: Crude staph i/lo- 

 >nycin: Light tan powder; m.p. 138-140°C (decom- 

 position); sinters at 130°C. [aj^ = -124° (c = 0.5 

 per cent in ethanol). N = 7.98%. Most stable to 

 boiling at neutrality (2). Distinguished from 

 streptogramin by paper chromatography (sta- 

 tionary phase: propylene glycol; mobile phase: 

 benzene) (1). Factor S: Weak acid. White needles; 

 m.p. 240-242°C; sinters at 1G5-167°C. If kept for a 

 few minutes in a bath at 170~175°C, a biologically 

 active substance showing only the 240-242°C 

 melting point is obtained. X = 7.98%. [a]„ = 

 — 28.0° (c = 1.0 per cent in ethanol). Ultraviolet 

 absorption maxima at 207 (E\°lm 590) and 304 m/x 

 (^^cm 86) in methanol. Infrared spectrum given in 

 reference 2. Very soluble in chloroform and di- 

 methyl formamide. Soluble in ether to 0.1 per 

 cent; methanol, 0.5 per cent; ethanol, 1.5 per cent; 

 benzene, 2.5 per cent; acetone and ethyl acetate, 

 3 per cent; and dioxane, 4 per cent. Insoluble in 

 water and petroleum ether. More stable than Mi . 

 At 37°C for 24 hours an inactive yellow precipitate 

 is formed. Addition of 0.1 per cent H2O2 prevents 

 formation of the precipitate, but not loss of ac- 

 tivity. pKr, = 9.0 in ethanol, or 7.7 in dimethyl- 

 formamide-water (1:2). C38-39H47-48N6O9 : C = 

 62.80%; H = 6.57%; N = 11.47%; O = 19.43%; 

 C— CH;i = 4.36%; N— CH, = 2.37%. No alko.xyl 

 groups. Brown-red color in FeCls test. Positive 



ninhydrin test. Negative 2,4-dinitrophenylhydra- 

 zine, Tollen, Fehling, KMn04 , Br in CCI4 , biuret, 

 Molisch, and Ehrlich tests. Hydrolysis products 

 include threonine, a-aminobutyric acid, and pro- 

 line, and possibly norvaline and phenylalanine. 

 The chemical structure of factor S has recently 

 been elucidated (7). Factor Mi : Neutral sub- 

 stance. Light tan powder; m.p. 165-167°C (de- 

 composition). [a]u = —190° ± 2° (c = 0.5 per cent 

 in ethanol) ; —174° ± 2° (c = 0.5 per cent in meth- 

 anol). Ultraviolet absorption spectrum maximum 

 at 216 rrifj. (E\^lra 582) and an inflection at 270 niju 

 (EWm 200) (methanol). Very soluble in chloroform 

 and dimethylformamide. Approximate solubilities 

 (per cent) : ether, 0.1 ; benzene, 0.3; ethyl acetate, 

 0.5; acetone, 2; methanol and ethanol, 4; dioxane, 

 5. Insoluble in water and petroleum ether. CosHse- 

 NsOs : C = 61.99%; H = 6.75%; N = 7.59%; O = 

 23.52%; C— CH:i = 7.09%; N— CH3 = 2.73%. No 

 alkoxyl groups; two carbonyl groups. Molecular 

 weight, 555 to 590. No acetylable hydroxyl groups. 

 Green color with FeCL test. Positive 2,4-dini- 

 trophenylhydrazine, Tollen, Fehling, Schiff 

 (weak), KMnOj , Br in CCI4 , and Ehrlich tests. 

 Negative Angeli-Rimini, Fe(OH)9 , biuret, nin- 

 hydrin, and Molisch tests. Hydrogenation prod- 

 ucts include at least two having no biological 

 activity and no Ehrlich reaction. Hydrolysis prod- 

 ucts include glycine and proline. Aromatic ring is 

 present (2). Factor Mn : Related to Mi . Positive 

 Ehrlich reaction (2). 



Biological activity: Active on gram-positive bac- 

 teria and mycobacteria. Not active on gram-nega- 

 tive bacteria or C. albicans (1). Factor S has a 

 synergistic action with Mi and Mn . Factors Mi 

 and Mil are more active on Staph, aureus and 

 Sarcina lutea than is S. S is 3 times more active on 

 B. subtilis than Mi . Mi is active in vitro at 1.2 

 Mg per ml on M. tuberculosis H37Rv. No activity on 

 M. tuberculosis H37Rv infections in guinea pigs 

 (3). Active in mice on Streptococcus pyogenes (1). 

 Factor S is not synergistic with penicillin, erythro- 

 mycin, streptomycin, or chlortetracycline. Mn 

 reduces the activity of Mi on staphylococci. Anti- 

 biotic PA 114A activity is enhanced by S and 

 slightly decreased by Mi . PA 114B enhances the 

 activity of Mi and S. The activity of Mi + S is 

 greater than that of PA 114A + PA 114B. Cross- 

 resistance exists between staphylomycin, PA 114 A 

 and B, and streptogramin. 



Toxicity: Crude staph ijhDuyci n: 50 mg per kg 

 tolerated by mice (1). Purified staphylomycin: 

 Nontoxic applied topically to human beings. Tox- 

 icity re|)ute(lly low in experimental animals (5). 



