Abstract
Five kinds of purified tuberculin protein, Seibert's PPDs, IP48 of Bretey and Lamensans, Takeda's TA2 and our π and πT, were prepared from the same lot of culture filtrate of tubercle bacilli for comparative evaluation of the methods of purification.
1. The yield of π was rather small, and the others about equally large.
2. In chemical determination, the content of DNA and polysaccharides was smallest in PPDs and about equal in the rest. The DNA content of PPDs was also found to be small by absorption spectra and electrophoresis.
3. Electrophoretic analyses showed the presence of some protein components of slow mobility besides the main protein component in PPDs and TA2, though it was not recognizable in π or πT, and recognizable only in a small amount in IP48.
4. The amount of potency recoverable in purified tuberculin protein was about 65 to 100 per cent of that of its original culture filtrate.
5. Certain problems suggested by these results concerning a method of purification to be adopted in the preparation of tuberculin protein for routine use have been discussed.
