Chapter VI — 105 — Enzymes, etc. 



tinomycetes has been demonstrated, as mentioned previously (p. 97). 

 The ability of certain strains of S. griseus to produce vitamin B12 has 

 also been established (p. 191). 



Oxidative Mechanisms:— Actinomycetes possess a number of oxida- 

 tive mechanisms, only few of which are recognized at the present time. 

 Attention may be called, for example, to the ability of "resting cells" of 

 certain species of Streptoviyces to transform aestradiol to oestrone (507). 

 According to Turfitt (430, 431), various species of Nocardia are 

 capable of attacking various steroids, with the possible exception of 

 halogen-substituted derivatives. The oxidation of cholesterol results 

 in the formation of a cholesterone, followed later by molecular fission, 

 the products of which may be utilized by the organisms for their fur- 

 ther growth. Various actinomycetes are also capable of producing 

 penicillinase (506). 



