CHAPTER IV 

 THE TRANSMISSION OF PROTEIN CHANGE 



1. Multiplicable Denaturase 



Living cells are essential for the multiplication of viruses. Viruses 

 can multiply only in the living cells. Viruses may cause a change in 

 the structure of protoplasm protein of host cells ; as a result the protein 

 may be endowed autocatalitically with the virus activity. In this respect 

 viruses may be looked upon as a kind of denaturase. However, they 

 are, if so, by no means the denaturase in a narrow sense. An enzyme 

 capable of converting a native protein into a "denatured" state is usually 

 termed denaturase, but the change in the protoplasm protein due to 

 viruses never appears to be a "denaturation", and hence viruses, if 

 necessary, should be called "transnaturase" instead of denaturase. If it 

 was impertinent to regard viruses as an enzyme, it would be considered 

 at least as an agent capable of causing a transnaturation in the proto- 

 plasm protein, There are, however, many reasons to regard viruses as a 

 kind of enzymes, a full account of which will be given in a later chapter. 



Each virus is antigenically specific. Thus, animals infected or 

 treated experimentally with a virus give rise to an antibody capable of 

 reacting specifically with the virus. The virus is deprived of its acti- 

 vity by the antibody. 



The appearance of virus-antigenicity in the host cell protein follow- 

 ing a virus infection may be ascribed to the occurrence of a specific 

 structural change in the protoplasm protein by the virus action, and 

 owing to the change the cells may fall into a pathological condition. 

 Thus viruses can be regarded as multiplicable transnaturase of proto- 

 plasm protein. 



Knignt (56) showed the existence of a difference in the amino acid 

 composition between the influenza virus particles and those separated 

 from the normal hen's embryo from which the virus particles were 

 isolated, indicating that the change of the protoplasm protein due to 

 the virus can effect the amino acid composition. According to Andreae 

 and Thompson (57) chromatogram of healthy and leaf-roll infected 

 potato tubers revealed a striking and consistent difference in the 

 occurrence of tryrtophane and tyrosine. Rafelson et al. (58) found 

 that the presence of Theiler's virus stimulated the incorporation of 

 radioactive carbon from glucose into most of the amino acids of minced 



