682 THE BIOCHEMISTRY OF B VITAMINS 



acidi, and either 6,7-dimethyl-9-(D,l'-xylityl)isoalloxazine or 9-(d,1' 

 arabityl)isoalloxazine inhibits the growth of an unidentified strain of 

 lactic acid bacteria. 50 



The following isoalloxazines have been reported to be inactive as 

 inhibitory analogues of riboflavin for Bacillus lactis acidi and the uniden- 

 tified strain of lactic acid bacteria: 9-(L,l'-arabityl)-, 9-hydroxyethyl-, 

 3-methyl-9- (D,l'-sorbityl) -, 5,6-dimethyl-9- (L,l'-arabityl) -, 6,7-di- 

 methyl-9- (D,l'-sorbityl) -, 3,6,7-trimethyl-9- (D,l'-sorbityl) -, 6,7-tetra- 

 methylene-9-(L,l'-arabityl)-, 5,6-benzo-9-methyl-, 9-phenyl-, 6-methyl- 

 9-(D,r-ribityl)isoalloxazine, 6,7-dimethyl-9-isoalloxazineacetic acid, and 

 9-isoalloxazineacetic acid. l,2-Dimethyl-4-amino-5-D,r-ribitylamino- 

 benzene and the corresponding 4-nitro derivative are also inactive. 50 



Although 2-amino-4,5-dimethyl-l,D-ribitylaminobenzene inhibits the 

 oxidation of riboflavin by Pseudomonas riboflavina, the inhibition does 

 not appear to be competitive. 57 No growth-inhibiting effect of 2-amino- 

 4,5-dimethyl-l-ribitylaminobenzene, even at relatively high concentra- 

 tions, is obtained with Lactobacillus casei. 57 



p-Monomethylaminoazobenzene and p-dimethylaminoazobenzene, 

 which are hepatic carcinogens, inhibit the growth of both Lactobacillus 

 casei and Saccharomyces cerevisiae. 67 Riboflavin tends to prevent the 

 toxicity of these compounds for each organism. 67 



Bibliography 



1. Kuhn. R., Gyorgy, P., and Wagner^Tauregg, T., Ber., 66, 317, 576, 1034 (1933). 



2. Blyth, A. W., /. Chem. Soc, 35, 530 (1879). 



3. Bleyer, B., and Kallmann, 0., Biochem. Z., 155, 54 (1925). 



4. Ellinger, P, and Koschara, W., Ber., 66, 315, 808, 1411 (1933). 



5. Karrer, P., Schopp, K., and Benz, F., Helv. Chim. Acta, 18, 426 (1935). 



6. Euler, H. v.. Karrer, P., Malmberg, M., Schopp, K., Benz, F., Becker, B., and 



Frei, P., Helv. Chim. Acta, 18, 522 (1935). 



7. Kuhn, R., Reinemund. K., Kaltschmitt, H., Strobele, K., and Trischmann, H., 



Naturwiss., 23, 260 (1935). 



8. Kuhn, R., Reinemund, K., Weygand, F., and Strobele, K., Ber., 68, 1765 (1935). 



9. Warburg, 0., and Christian, W., Naturwiss., 20, 688, 980 (1932) ; Biochem. Z., 258, 



496 (1933); 263, 228 (1933); 242, 206 (1931); 254, 438 (1932); 257, 492 (1933); 

 266, 377 (1933). 



10. Banga, I., and Szent-Gyorgyi, A., Biochem. Z., 246, 203 (1932) ; Banga, I., Szent- 



Gyorgyi, A., and Vargha, L., Z. physiol. Chem., 210, 228 (1932). 



11. Theorell, H., Biochem. Z., 275, 37 (1934); Kuhn, R., and Rudy, H., Ber., 68, 



383 (1935). 



12. Kuhn, R., Rudy, H., and Weygand, F., Ber., 69, 1543 (1936); Kuhn, R., and 



Rudy, H., Ber., 69, 1974 (1936). 



13. Karrer, P., and Quibell, T. H, Helv. Chim. Acta, 19, 1034 (1936). 



14. Karrer, P., and Strong, F. M, Helv. Chim. Acta, 18, 1343 (1935). 



15. Kuhn, R., Vetter, H., and Rzeppa, H. W., Ber., 70, 1302 (1937). 



16. Karrer, P., Euler, H. v., Malmberg, M., and Schopp, K., Svensk. Kem. Tid., 



47, 153 (1935). 



17. Karrer, P., Salomon, H., Schopp, K., Benz, F., and Becker, B., Helv. Chim. 



Acta, 18, 908 (1935). 



