Proteins and Enzymes

ID #1046

In my notes, I wrote that the energy of activation does not come from heat because it denatures proteins, which makes sense to me. Then, under that, I have written that the energy of activation instead comes from enzymes. I don't quite understand that. I thought enzymes lowered the activation energy, but I did not know that they provided it as well.

It's really just semantics and perspective. The end result is that the contribution of the enzyme gets you over the "hill" faster than you would if enzyme were absent. Think of it this way. A reaction may take a great deal of heat energy to happen in the absence of enzyme -- the reactants really need to be "fired up" to collide hard enough for their electron clouds to overcome their repulsion for each other, which is a requirement for forming a new bond. Now if an enzyme grabs the substrates, it can put a strain on them, pushing them closer together so that it now takes just a normally-available amount of heat to overcome that electron repulsion. This will make the reaction proceed quickly, and doesn't denature your cellular proteins!

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