Abstract
The characteristic spectral properties of normal proteins and their derivatives stimulate similar studies with material showing special biological activity. Previous investigations along a similar line were hampered by the use of impure material. 1 Therefore, for the studies here presented several preparations of tuberculin, purified according to the methods of Seibert and Munday, 2 were used.
Preparations made from human, bovine and avian tubercle bacilli were studied. In the case of the human tubercle bacillus there were 5 different fractions: (1) 3 purified unheated tuberculins, (2) a purified Old Tuberculin, and (3) a purified Old Tuberculin made from cultures in a synthetic medium. Products made similarly from the non-pathogenic acid-fast bacilli, timothy, butyricum and smegma, and purified protein, proteoses, and a cyclic amino acid, served as controls. The initial concentration of all of these slightly alkalinized solutions was one per cent. In these studies a small Quartz Hilger spectrograph was used. Carbons containing iron provided the spectrum.
In all preparations made from the 3 strains of tubercle bacilli, the spectrograms showed a specific absorption band with a maximum at 265 mμ. The concentration at which this band appeared varied in the different preparations and seemed to correspond closely to their respective tuberculin potencies. The more potent preparations showed the special absorption band at a higher dilution than the less active samples. This was observed not only in the case of the 3 different tubercle bacillus strains but also in different fractions from the same strain (human). The preparations made from the 3 nonpathogenic strains of bacilli failed to show this special absorption band.
Irradiation with ultra-violet light, known to destroy the potency of tuberculin, seems to increase the total absorption and at the same time destroys the specific absorption band.
The detailed data and spectrograms with a discussion concerning their significance and suggestions for further practical use will be presented elsewhere.
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