Do enzymes act ON the the transition state?

[zanzounita]

In a TPR book, it says that they do NOT act on the transition state, yet it "stabilizes the transition state". Anyone?

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[NYGirl12]

Enzymes lower down the activation energy of a reaction by stabilizing the transition state.

 

[ddev]

Well enzymes bind more tightly to transition states than either the reactants or the products

 

[killinsound]

...

enzymes bind the reactants and have them in favorable positions to achieve the post-transition state

 

[spicedmanna]

Enzymes lower down the activation energy of a reaction by stabilizing the transition state.

That's the explanation that I'm familiar with.

 

[Phlame217]

The simple explanation is:

The larger the difference between starting point and the transition state (the top of the curve), the less stable the transition state is (being so high in energy); Therefore if you lower activation energy (as an enzyme does by favourable aligning two molecules to react in a lock and key sort of way), the peak drops since activation energy drops therefore the transition state becomes more stable.

That kinda puts everything together mentioned before.

 

[biggiesmallsiz]

Well enzymes bind more tightly to transition states than either the reactants or the products

this is true. in biochem, i learned that analogs most resembling the t-state had the greatest affinity for the enzyme active site.

 

[paranoid_eyes]

stabilizing the transition state simply means that the transition state WITHOUT the enzyme is less stable than the the transition state WITH the enzyme.

usually, instability arises from partial +/- charges which are stabilized by charged residues at the enzyme's active site

 

[Maxprime]

For purposes of the MCAT, know that they lower the activation energy and do not change delta G - KISS (keep it simple, stupid).

For the joy of learning, take a graduate level class solely on enzyme kinetics and then try your best to forget it all over winter break.