IX, THE REJUVENATION OF VIRUSES 



191 



The peptide chains in the native protein molecules are folded as 

 shown in I of this Figure ; in this state almost all the polar groups 

 of the side chains may exist in mutual saturation, whereas, by the 



n 



III 



Fig. 21. Diagram of protein denaturation. After. Haurowitz : Chemi- 

 stry and Biology of Proteins, 1950, (a little modified). 



action of denaturating agent, the chains are unfolded as II, thereby 

 polar groups of the side chains are set free, but as this form is un- 

 stable, refolding will follow soon to take the form III which is different 

 from I. 



At first, mention should be made as regards the phase II in Fig. 21 

 where peptide chains are unfolded and polar groups are set free. In 

 this phase proteins may be in an activated state owing to this freed 

 polar groups which enable them to combine with one another or to 

 act upon other substances. For example, red blood corpuscles are 



