Abstract
The procedure described recently for the isolation of protein fractions from a scarlatinal strain of Streptococcus hemolyticus 1 has been applied with slight modification to the Timothy grass bacillus, Mycobacterium phlei.
Fresh cultures were frozen and dried, extracted in the cold with acetone and purified ether during 48 hours, ground in a ball mill until intact organisms were no longer visible, and again extracted in the cold with acetone and ether during several hours. The cell residues were then stirred for about 6 hours each in the cold with buffer at pH 4 (C), 6.5 (D, D'), water containing enough N NH4OH to keep the pH at 8.3-8.5 (E), water made alkaline to about pH 9 (F), and water made alkaline to about pH 11 (G). The residual material was shaken with 0.5% NaOH at room temperature (K). The properties of the fractions obtained by acidifying the extracts are given below, D'differing from D only in the necessity for the use of acetone in precipitating it from the opalescent supernatant from D.
It is thus seen that a close parallel exists with the corresponding fractions of the hemolytic streptococcus. In general levorotation increases and nitrogen and phosphorus decrease with increasing alkalinity of the solution used for extraction. The lability of the D fraction is not as great in the case of the Timothy grass bacillus, only 20% N and 60% P being split off in 0.02 N NaOH at 25° for 24 hours. Fraction D corresponds to some extent with the “water-soluble protein”, K, with the “alkali-soluble protein” obtained according to Johnson's scheme. 2 The reactivity of the fractions toward antihuman type serum is surprising in view of the specificity of the tuberculin proteins. 3
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