II. CHEMISTRY 



503 



amounts of sulfone the yeast growth did not increase above a relatively 

 low maximum which was only about one-third of the maximum growth ob- 

 tained with biotin. Biotin sulfone was found to be approximately 0.1% 



TABLE IW 

 Growth-Promoti.ng Activities of Analogs of Biotin and Oxybiotin 



" Active for Saccharomyces cerevisiae (25 strains), S. chodati, S. macedoniensis, Endomycopsis fibuliger 

 Debaromyces matruchoti v. subglobosus, Mycoderma valida, Mycotorula lactis, Schizosaccharyom,yces pontbe, Torula 

 lactosa, Zygosaccharomyces lactis, Z. marxianus, Neurospora crassa, N. sitophila, Ceratostomella, ips 438, Cera- 

 tostorrtella montium, Leuconostoc mesenteroides, Penicillium notatum 21464, Escherichia coli 58, Ceratostomella 

 reukanfi, Schwanniomyces occidentalis 116.'"' '"• •". ut Inactive for Ceratostemella pint 416, Sordaria fimicola, 

 Lactobacillus arabinosus, Rhizubium trifulii 205,"" and I'enicillium chrysogenum 62078."'- "" 

 Compound competitively inhibits utilization of biotin for this organism. 



■^ Only 35 to 50% of optimal growth obtained with biotin is attained. 



as effective as biotin when the activities were compared at the level of 

 one-fourth maximum growth increase due to l)iotin. The same ratio (0.1 %) 

 appears to apply also to the curative effect of biotin sulfone on rats with egg 

 white injury. 



The stimulation of yeast growth by biotin sulfone is dependent on the 

 presence of aspartic acid in the medium. Asparagine could not be sub- 

 stituted for aspartic acid.'^' 



