404 VIII. CHOLESTEROL AND RELATED STEROLS 



could be oxidized to the corresponding keto derivatives by Proactinomyces 

 spp. Apparently all hydroxysteroids are attacked, but those having shorter 

 side-chains or those without side-chains give a lower yield of ketones. All 

 bonds such as nuclear and side-chain double bonds remain unattacked, 

 and ester linkages are not broken. Horvath and Kramli^^" observed that 

 the cholesterol — >• cholestenone reaction was effected much more success- 

 fully with a soil bacterium, Azotobacter spp. (which fixes free nitrogen) than 

 with Proactinomyces. In addition to the formation of the ketone, Azoto- 

 bacter also dehydrated the sterol ring, with the formation of sufficient 7- 

 dehydrocholesterol to render its isolation possible. 



Other organisms which have been found to effect the oxidation of hy- 

 droxy-steroids to the keto derivatives have been separated from yeast by 

 Italian workers. Ercoli^^^ isolated Micrococcus dehydrogenans from baker's 

 yeast; it converted androstenediol to pregneninolone. Arnaudi"^ also 

 described Flavobacterium {Micrococcus) dehydrogenans, which oxidized 

 dehydroandrosterone to androstenedione. Ercoli and Mohna,^^' in 1944, 

 first described the activity of F. androstenedionicum, which converted 

 androstenediol to androstenedione, and Molina and Ercoli^^^ that of F. 

 carbonilicum. This new microorganism from yeast was able to oxidize 

 dehydroandrosterone to androstenedione, and also androstenediol to a 

 mixture of testosterone and androstenedione. In general, these organisms 

 oxidize the nuclear hydroxyl groups of the steroid compounds devoid of the 

 C-17 side-chain. Bacillus pseudodiphthericus {Corynebacterium hoffmanni), 

 a pathogenic organism from throat cultures, oxidizes estradiol to estrone. '^^ 

 Schmidt et aU^^ observed that the intestinal bacterium, Alcaligenes faecalis 

 (Bacterium fecalis alcaligenes) , could bring about a stepwise oxidation of 

 the hydroxyl groups of cholic acid. Escherich's intestinal bacillus (Escher- 

 ichia coli)^^'' has been found to produce this same reaction. 



In more recent work, Turfitt^"'^ demonstrated that the oxidation of the 



"" J. Horvdth and A. Krd,mli, Nature, 160, 639 (1947). 



"lA. Ercoli, Biochim. e. temp, sper., 28, 125-130 (1941); Chem. AbsL, 38, 2987 

 (1944); Z. physiol. Chem., 270, 266-270(1941). 



*^^ C. Arnaudi, Boll. sez. Hal. soc. intern, microbiol., 2, 208-211 (1939); Chem. Ahst., 

 34, 3301 (1940); Zentr. Bakteriol. Parasitenk., Abt. II, 105, 352-366 (1942). 



313 A. Ercoli and L. Molina, Boll. ist. sieroterap. milan., 23, 158-163, 175-180 (1944); 

 Chem. Ahst., 40, 3152-3153 (1946). 



"^ L. Molina and A. Ercoli, Boll. ist. sieroterap. milan., 23, 164-167 (1944); Chem. 

 AbsL, 40, 3152(1946). 



315 W. Zimmermann and G. May, Zentr. Bakteriol. Parasitenk., Aht. I. Orig., 151, 462- 

 466 (1944). 



316 L. H. Schmidt, H. B. Hughes, M. H. Green, and E. Cooper, /. Biol. Chem., 145, 

 229-236(1942). 



317 L. H. Schmidt and H. B. Hughes, U. S. Patent No. 2,360,447 (Oct. 17, 1944). 



