PYRIDOXINE 



6. T. W, Birch and P. Gyorgy, Biochem. J., 1936, 30, 304. 



7. A. M. Copping, ihid., 845. 



8. C. E. Edgar and T. F. Macrae, ibid,, 1937, 31, 879, 893. 



9. C. E. Edgar, M. M. El Sadr and T. F. Macrae, ihid., 1938, 32, 2225. 



10. H. Chick, T. F. Macrae and A. N. Worden, ibid., 1940, 34, 580. 



11. H. Chick, M. M. El Sadr and A. N. Worden, ibid., 595. 



2. ISOLATION OF PYRIDOXINE 



The isolation of vitamin Bg in crystalline form was announced in 

 1938 from four different laboratories. P. Gyorgy ^ and S. Lepkovsky ^ 

 obtained it from rice bran and yeast respectively by eluting the 

 fuller's earth adsorbate with baryta and precipitating the active 

 substance from the eluate with phosphotungstic acid, after removal 

 of inert material by precipitation with alcohol, mercuric chloride and 

 similar methods. The precipitate was decomposed with baryta, and 

 the filtrate crystallised on being concentrated. 



J. C. Keresztesy and J. R. Stevens ^ isolated the vitamin from an 

 adsorbate of rice extract, whilst R. Kuhn and G. Wendt * used yeast, 

 in which they stated the vitamin was present as a non-dialysable 

 protein complex with the properties of an enzyme. Pyridoxine was 

 also isolated from rice bran in 1940 by T. Matukawa,^ who used frac- 

 tional adsorption, acetylation and extraction with ether followed by 

 hydrolysis. 



According to J. V. Scudi,® rice bran contained a water-soluble 

 conjugate of low molecular weight, in addition to free pyridoxine. 

 This was not precipitated by the usual protein precipitants, and 

 could be adsorbed on acid clay and eluted in a similar manner to 

 pyridoxine. 



References to Section 2 



1. P. Gyorgy, /. Amer. Chem. Soc, 1938, 60, 983. 



2. S. Lepkovsky, Science, 1938, 87, 169 ; /. Biol. Chem., 1938, 124, 125. 



3. J. C. Keresztesy and J. R. Stevens, Proc. Soc. Exp. Biol. Med., 



1938, 38, 64 ; /. Amer. Chem. Soc, 1938, 60, 1267. 



4. R. Kuhn and G. Wendt, Ber., 1938, 71, 780, 11 18. 



5. T. Matukawa, /. Pharm. Soc, Japan, 1940, 60, 216. 



6. J. V. Scudi, /. Biol. Chem., 1942, 145, 637. 



3. CHEMICAL CONSTITUTION OF PYRIDOXINE 



Pyridoxine 



Pyridoxine hydrochloride has the empirical formula, C8H12O3NCI, 

 and its structural formula was worked out independently by R. Kuhn 

 and his fellow-workers in Germany, and by a group of workers in the 

 U.S.A. 



298 



