192 



THE ACTIXOMYCETES, Vol. I 



that oxidize progesterone. Schiesser studied 

 cortisone-oxidizing enzymes. Harris et al. 

 (1957) found that »S'. globisporus, S. virido- 

 chromogenes, and other streptomycetes are 

 capable of deacetyhition and oxidation of 

 dehych'oepiandrosterone acetate. 



A detailed discussion of the hterature on 

 steroid oxidation by actinomycetes is found 

 in the re\'iews of Eppstein et al. and Wett- 

 stein (1955). 



Other Enzymes 



Numerous other enzymes and coenzymes 

 have been found to be produced by actino- 

 mycetes. It is sufficient to mention coen- 

 zyme A (Gregory et al., 1952). The abil- 

 ity of various nocardias (N. asteroides, N. 

 pelletieri) to bring about the demyeliniza- 

 tion of bovine spinal cord may be due to an 

 enzyme system. Some of these mechanisms 

 produced by Streptomyces and Nocardia 

 species are thermostable and others are 

 thermolabile (Adelson et al.). Anaerobic ac- 

 tinomycetes are able to produce acid phos- 

 phatase (Howell and Fitzgerald, 195.3). 



Wayne et al. developed aryl sulfatase tests 

 for differentiating saprophytic mycobacteria 

 from the tuberculosis organisms. This study 

 was of particular interest in differentiating 

 atypical mycobacteria and nocardias. Only 

 21 per cent of all nocardias tested and none 

 of the streptomycetes or corynebacteria 

 produced the enzyme (Table 47). Almost 

 all mycobacteria hydrolyzed demonstrable 

 amounts of phenolphthalein disulfate if sufh- 

 cient inoculum was used and permeability 

 diffei"ences compensated for. The interesting 

 conclusion was rea(^hed that if M. rhodo- 

 chrous is a true mycobacterium, it is the only 

 member tested which d()(\s not j^roduce aryl 

 sulfatase. 



The production of enzymes of the isoci- 

 tritase pathway was demonstrated by Bardi 

 et al. (1958) for .V. riigosa. 



Lara (1952) reported that enzyme prepa- 

 rations of the N. corallina group can be ob- 

 tained by extracting ahmiina ground cells. 

 The activity of these extracts against thy- 

 mine and uracil was demonstrated only when 

 methylene blue was added. These com- 

 pounds were oxidized to substances having 

 the over-all composition of 5-methyl bar- 

 bituric acid and barbituric acid, respectively. 

 In one experiment uracil was formed from 

 thymine; the results of many other experi- 

 ments, however, indicated that the demeth- 

 ylation of the latter did not normally pro- 

 ceed under the conditions used, leading to 

 the conclusion that normallj^ uracil is not an 

 intermediate product in the decomposition 

 of thymine. Cell-free extracts of N. corallina 

 with activity towards thymine, uracil, and 

 barbituric acid were obtained only from 

 cells grown in either thymine, uracil, or bar- 

 bituric acid; enzyme preparations from glu- 

 cose grown cells were de^■ oid of such activity. 

 This points to the adaptive nature of the 

 enzyme system (Fig. 78). 



Barbituric acid was hydroh'zed l)y the 

 enzyme preparation with the formation of 1 

 mole of CO2 , 2 moles of NH3 , and 1 mole 

 of malonic acid, for a pathway of thymine 

 and uracil degradation according to the fol- 

 lowing scheme: 



Thymine 



5-Methvl barbituric acid 



Uracil — > Barbituric acid 



Malonic acid -\- Urea 



^ i 

 CO2 NH3 



