STUDIES ON THE FRACTIONATION OF TUBERCULIN AND JOHNIN .1. FRACTIONATION OF TUBERCULIN PROTEINS

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Abstract
The authors have prepared fractions from tubercle bacilli culture filtrates which were more specific than Bureau of Animal Industry (BAI) regular tuberculin. The most specific fraction obtained in appreciable yields was prepd. by a 3-step process: (1) culture filtrate fractionated by acidification to remove material soluble at pH 4.7 and insoluble at pH 5.2; (2) dialysis left most of the active material in the non-dialyzable ("endo") soln. (3) this "endo" soln. was treated with alcohol, and the precipitate formed was dissolved in 90% phenol and further fractionated by the addition of alcohol. The amino acid content was detd. for 2 fractions; one isolated from human-type tubercle bacilli culture filtrate and the other from bovine-type tubercle bacilli culture filtrate. The amino acids were assayed microbiologically for 17 amino acid and tryptophan was detd. colorimetrically.