It was obvious-to me at any rate-that the answer was to why an enzyme is able to speed up a chemical reaction by as much as 10 million times. It had to do this by lowering the energy of activation-the energy of forming the activated complex. It could do this by forming strong bonds with the activated complex, but only weak bonds with the reactants or products.
Linus PaulingThe McCarthy period came along...and many of the other scientists who had been working on these same lines gave up. Probably saying "Why should I sacrifice myself? I am a scientist, I am supposed to be working on scientific things, so I don't need to put myself at risk by talking about these possibilities." And I have said that perhaps I'm just stubborn... I have said "I don't like anybody to tell me what to do or to think, except Mrs. Pauling."
Linus PaulingIt has been recognized that hydrogen bonds restrain protein molecules to their native configurations, and I believe that as the methods of structural chemistry are further applied to physiological problems it will be found that the significance of the hydrogen bond for physiology is greater than that of any other single structural feature.
Linus Pauling