Timeline for Peptide bond formation involving side chains of charged amino acids
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 17, 2019 at 16:25 | vote | accept | Aniruddha Deb | ||
| Dec 17, 2019 at 14:39 | comment | added | Karsten♦ | @Jan That depends on the concentration of water (just like esters). If you run this in organic solvent, reactants may be favored, certainly when you continuously remove the water. With water as a solvent, the products are favored (enzymes can't change the equilibrium constant, and there is no ATP in the digestive tract for a coupled reaction - we would be unable to digest protein if the products weren't favored). | |
| Dec 17, 2019 at 14:27 | comment | added | Jan | Let me rephrase that: afaik, the equilibrium $\ce{RCO-NHR' + H2O<=>RCOOH + H2NR'}$ favours the reactant side thermodynamically at neutral pH which would be in contradiction to your first paragraph. | |
| Dec 17, 2019 at 14:22 | comment | added | Karsten♦ | @Jan Yes, that is why reactions from anhydride to amide (or from amide to carboxylate) work without being coupled to the hydrolysis of ATP or some other source of free energy. | |
| Dec 17, 2019 at 13:56 | comment | added | Jan | Actually, as far as I am aware the amide bond is the ‘bottom of the thermodynamic well’, i.e. the most stable possible carboxyl derivative. Digestive enzymes (as all enzymes) have a couple of tricks to influence kinetics and make the reaction work. | |
| Dec 17, 2019 at 13:33 | history | edited | Mathew Mahindaratne | CC BY-SA 4.0 |
Corrected some typos and edited to improve formatting and clarity.
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| Dec 17, 2019 at 13:21 | history | answered | Karsten♦ | CC BY-SA 4.0 |