The effect on vitamin B2 of treatment with nitrous acid

Abstract

The work contained in this paper was undertaken in consequence of the conclusion published by Levene {Jour. Biol. Chem. 79: 465. 1928.) that the heat-stable, anti-dermatitis vitamin B2 (unlike the antineuritic vitamin B1) was destroyed when deaminized by the action of nitrous acid. The vitamin B2 concentrate used was prepared by decomposition with H2S of the precipitate formed when Pb acetate is added to a dilute acetic acid extract of brewers'' yeast (Chick and Roscoe, 1929, Biochem. J. 23: 504). Deaminization was carried out by the method of Peters (1924, Biochem. J. 18: 858) and the amino-N, as estimated by Van Slyke''s method, was thereby reduced from 0.091 gm. per 100 gm. of original yeast, dry weight, to 0.016%. Nevertheless, no diminution in the vitamin B2 potency of the preparation could be detected in tests made by the method of Chick and Roscoe (1928, Biochem. J. 22: 790).