Chemistry
The Effect of Ionic Strength on the Rate of Enzyme-Catalyzed Reactions
Quick fact
Enzymes with highly charged active sites can show a two- to tenfold change in their reaction rate when the salt concentration in the surrounding solution is raised from very low to moderate (e.g., from 1 mM to 100 mM). This happens because dissolved ions shield the electrostatic attractions and repulsions that guide substrate binding.
Why this is interesting
You’ve probably seen in the lab that adding a pinch of salt can speed up an enzyme reaction—or shut it down completely. What’s going on? That’s the hidden power of ionic strength.