Peptide bonds form during translation within ribosomes and connect amino acids into polypeptide chains that fold into protein structures. A peptide bond is a covalent bond formed through a dehydration synthesis reaction between the carboxyl group of one amino acid and the amine group of the next. This reaction involves the loss of a water molecule as the carboxyl oxygen and amine hydrogen are removed to connect the amino acids. Peptide bonds make up the backbone of proteins by linking the 20 common amino acids together end to end.

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

2. 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..

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

4. 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”.

5. 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
C
O
R
OH

6. 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?

7. 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 water
synthesis : to build
Dehydration synthesis reaction are commonly
used in cells for anabolic or synthesis reaction.

8. Watch this formation of peptide bond between two amino acids.
C
H
NH
H CH3
C
O
OH C
H
NH
H CH2
C
O
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