Abstract
1) Toxic principles of protein nature contained in the filtrates of five streptomyces cultures were purified by means of alcohol precipitation and zone electrophoresis. They were common in revealing both necrotic toxicity when injected intracutaneously into guinea pigs and cytotoxic effect against HeLa cell cultures.
2) They were all heat-labile particularly at pH 2.0, and the sedimentation constants were between 0.8 and 3.6. Four out of the five preparations were basic in nature.
3) With two preparations the production of antibody was proved upon intravenous injection into rabbits. Neutralization of the activity was proved with the antibodies towards these two principles.
4) Immunological analysis revealed that the proteins produced from two species of Str. Diastatochromogenes and two species of Str. Lavendulae are closely related. However, a protein isolated from Str. cellulosae was shown to be different from others. Acidic nature of the latter was also the difference from the remaining four which were basic in nature.
