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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: vernii on December 18, 2022, 05:09:21 AM

Title: Biomolecules
Post by: vernii on December 18, 2022, 05:09:21 AM

During the formation of a peptide bond, H2O is released. H+ is taken from NH2 and OH- from COOH( but it acts as acid right?, Then how?)

Title: Re: Biomolecules
Post by: Babcock_Hall on December 19, 2022, 07:22:12 AM

Do you mean how is a peptide bond biologically synthesized or how is it formed when a peptide chemist makes one?

Title: Re: Biomolecules
Post by: Borek on December 19, 2022, 07:38:14 AM

I believe OP has problems with the mechanism, that's what I gather from the earlier question about sulphonyl chloride reaction with NaOH.

Title: Re: Biomolecules
Post by: Babcock_Hall on December 19, 2022, 09:52:30 AM

@OP, It is not practical to make a peptide bond from two free amino acids.*  Instead, the Carboxylic acid is made into a derivative.  Regarding the biochemical synthesis of peptide, what is done is to make what an organic chemist might call an active ester, an ester with a hydroxyl group of transfer RNA.
*I suppose that one could draw out the mechanism for acid-catalyzed or base-promoted hydrolysis of a peptide bond.  The mechanism of formation would be the reverse, but the equilibrium favors hydrolysis.