多角体蛋白

In the course of the procedure to determine nucleic acids in the polyhedral bodies, or the inclusion bodies of virus particles, of silkworms, it was observed that the major part of the bodies treated with trichloroacetic acid (TCA) immediately dissolved in alcohol. The material dissolved in alcohol was proved to be protein in the previous paper. By the presence of TCA, the polyhedral protein dissolves in acetone and in methyl alcohol as well as in ethyl alcohol, but does not dissolve in water, ether, and benzene. This phenomenon can be attributed to the specialities of both the protein and the acid. Only the polyhedral protein dissolved in alcohol containing TCA, and no protein having such a property was observed (Table 2). The dissolution of the protein in alcohol is caused by a minute amount of some special acids (Table 3). TCA has the strongest effect. The acids which have stronger effect are generally stronger acids, and hydrogen ion is an indispensable factor to dissolve the protein in alcohol (Table 4). However, the effectiveness of acids has no direct relationship to their dissociation constants, and the kind of anions seems to be more important. It is very interesting to note that the two most effective acids, TCA and perchloric acid, are similar to each other in their structures on the electronic aspects. They have likewise three polar radicals around an atom. A linear relationship is observed between the concentration of TCA and the solubility of the polyhedral protein (Fig. 1). The protein dissolves in alcohol by 1 g. of its nitrogen per 0.01 mole of TCA. The polyhedral protein treated with TCA became insoluble in alcohol by dialysis against distilled water in the refrigerator. But the dialysed protein dissolved in alcohol by a new addition of TCA. From the freshly prepared alcoholic solution which was saturated with the protein upon the definite amount of TCA, the latter was rapidly removed away and gel-formation was brought about by dialysis against alcohol in the refrigerator (Table 5). A hypothesis to explain these phenomena was proposed.