26 A. L. PlERSTORFF 



toluol were examined. No traces of glucose, benzaldehyde, or hydro- 

 cyanic acid were found. The tests were performed in triplicate with 

 similar results. From this it must be concluded that amygdalase was 

 not produced. 



The presence of maltase was evident when maltose was used, but 

 this enzyme failed to appear, or at least to exert any influence in the 

 media, when amygdalin was substituted for maltose. Waksman 

 (in Jordan and Falk, 1928:270) makes the following statement: 

 "The presence of specific nutrients in the medium regulates the 

 quantitative formation of specific enzymes. Thus, the presence of 

 starch will increase the amylolytic power; the presence of proteins, 

 the proteolytic power, etc." The pH of both cultures was adjusted to 

 6.18, which is about the optimum for both enzymes. Either maltase was 

 not formed, as Knudson (1913) found with tannase, or the enzyme is 

 unstable in the absence of its substrate or products of its reaction, a 

 hypothesis advanced by Professor O. F. Curtis, of Cornell University, 

 to explain the increased amount of a given enzyme found in a culture 

 supplied with the specific substrate. Maltase is known to be unstable 

 above 0° C. 



Arbutase 



Cultures similar to those used with amygdalin were made with 

 arbutin. After sterilization the medium was clear, resembling dis- 

 tilled water in appearance, and gave negative results for sugar tests. 



After five days the culture tubes became turbid and had a faint 

 brown color. At the end of fifteen days the brown color was very dis- 

 tinct, indicating the formation of hydroquinone. Tests for sugar again 

 proved negative. To half of the cultures and checks, 2 per cent of 

 toluol was added. Six days later the cultures were distinctly darker, 

 and tests for reducing sugars proved positive. The same results were 

 obtained in two subsequent tests. The checks remained clear through- 

 out and gave no evidence of the formation of hydroquinone or of reduc- 

 ing sugars. 



What enzyme caused this reduction in the culture tubes? If amyg- 

 dalase was produced there should have been some reduction in the 

 cultures containing amygdalin. No evidence is found in the literature 

 that arbutin is hydrolyzed by maltase, as is stated for amygdalin. We 

 must accept either the facultative or qualitative production of enzymes, 

 or the view that enzymes which are specific for glucosides are produced 

 (Oppenheimer, 1925) as are enzymes which are specific for the various 

 sugars. If the latter view is adopted, then we shall have to say that 

 Bacillus amylovorus produces the enzyme arbutase, in conformity with 

 the terminology used for enzymes. 



