Peptide Bond

By: Ma. Luisa Ilumba Janessa Batilan Aivi Lianne Nayre Jacenzeart Comoda

In this learning we will examine the biochemistry behind the formation of peptide bonds.

Inside cells, peptide bonds are formed within ribosomes during a process called translation..

Proteins are polypeptides that are folded into specific three-dimensional structures.

Polypeptides are composed of amino acids Covalently bonded to each other like beads of strings.

The covalent bond that holds the amino acids together is called “peptide bond”.

All twenty amino acids share a common structure that includes:

a central alpha carbon covalently bonded to:

-A central carboxyl group- An amine group-A hydrogen- A variable R group

C

C

H

NH

H

CO

R

OH

Study the three amino acids below.

Can you identify the central alpha carbon?

Can you identify the carboxyl group?Can you identify the amine group?Can you identify the variable R group?

During protein synthesis or “translation”, amino acids are covalently bonded to each other through a peptide bond.

This reaction, which takes place within ribosome, is known as a “dehydration synthesis reaction”.

dehydration: loss of watersynthesis : to build

Dehydration synthesis reaction are commonly used in cells for anabolic or synthesis reaction.

Watch this formation of peptide bond between two amino acids.

C

H

NH

H CH3

CO

OH C

H

NH

H CH2

CO

OH

OH

An OH is removed from the carboxyl group of amino acid on the left.A H is removed from the amine group of amino acid on the left.

The OH and H form water, H20.This is dehydration because water has been lost.A covalent bond can now form between the amino acids. This is a peptide bond.

H2O