Key difference - glycosidic bond vs. peptide bond
Carbohydrates and proteins are essential components for the human body. Our body uses carbohydrates to meet its energy needs. We need proteins for our growth. Carbohydrates and proteins are complex compounds made up of small units. The building blocks of carbohydrates are monosaccharides . The building blocks of proteins are amino acids. Monosaccharides are bound together by glycosidic bonds and form complex carbohydrates. Amino acids are linked by peptide bonds that make up a protein. The main difference between a glycosidic bond and a peptide bond is that a glycosidic bond is formed when two carbon atoms of two different monosaccharides are linked together, while a peptide bond is formed when a carbon atom of one amino acid is linked to a nitrogen atom of another amino acid.
Key areas covered
1. What is a glycosidic bond - definition, formation, properties 2. What is a peptide bond - definition, formation, properties 3. Similarities between a glycosidic bond and a peptide bond - overview of the similarities 4. What is the difference between a glycosidic bond and a peptide bond - comparison of key differences
Key Terms: 1,4-glycosidic bond, 1,6-glycosidic bond, carbohydrate, covalent bond, glycosidic bond, monosaccharide, peptide bond, polypeptide, protein
What is a glycosidic bond?
A glycosidic bond is a type of covalent bond that occurs between two monosaccharides. This bond is found in sugar or carbohydrate molecules. Carbohydrates are made up of monosaccharides linked together by glycosidic bonds. A glycosidic bond is formed between two carbon atoms. A carbon atom is connected to another carbon atom via an oxygen atom.
Figure 01: Formation of a glycosidic bond between glucose and fructose
The number of glycosidic bonds a particular carbohydrate has depends on the number of monosaccharides present in that carbohydrate and the type of carbohydrate. For example, in linear carbohydrate molecules, the monosaccharides are linked to one another on their two sides; thus the number of glycosidic bonds present in this complex is equal to the value of the number of monosaccharides minus one.
If two monosaccharides are linked by a glycosidic bond, a disaccharide is formed . When a plurality of monosaccharides are bound to each other, an oligosaccharide is formed , and when the number of monosaccharides bound to each other is more than 50, a polysaccharide is formed. Sometimes a glycosidic bond can be found as an N-glycosidic bond or an S-glycosidic bond. Because here the two carbon atoms are bonded to each other via a nitrogen atom or a sulfur atom.
There are two main types of glycosidic bonds that can be formed between monosaccharides.
- 1,4-glycosidic linkage
- 1,6-glycosidic linkage
Figure 02: Two types of glycosidic bonds
A 1,4-glycosidic linkage is formed when the -OH group of a monosaccharide is attached to the first carbon, a condensation reaction with the -OH group is bonded to the fourth carbon of another monosaccharide passes. A 1,6-glycosidic linkage is formed when the -OH group of a monosaccharide is attached to the first carbon, a condensation reaction with the -OH group is bonded to the sixth carbon of another monosaccharide passes. In both processes, a water molecule is formed for each glycosidic bond formed.
1,4-glycosidic bond causes the formation of a carbohydrate with a linear chain. 1,6-glycosidic bond causes the formation of carbohydrates with branched structures. However, hydrolysis can break the glycosidic bond.
What is a peptide bond?
A peptide bond is a type of covalent bond that is formed between two amino acids. This creates the bond between a carbon atom of one amino acid and the nitrogen atom of the other amino acid. The basic structure of an amino acid consists of a central carbon atom that is bonded to a carboxyl group, an amino group, a hydrogen atom and an alkyl group. This alkyl group distinguishes an amino acid from another amino acid.
A condensation reaction takes place between two amino acids. The carboxylic acid of one amino acid reacts with the amine group of another amino acid, releasing a water molecule. The -OH group of the carboxylic acid group forms a water molecule that combines with a hydrogen from an amine group.
Figure 03: Formation of a peptide bond
The peptide bond is given as the -CONH bond because the bond is formed with these four atoms, as shown in the figure above. When two amino acids are linked together by a peptide bond, the end product is a dipeptide; if several amino acids are linked, one speaks of oligopeptides. If many amino acids are linked by peptide bonds, the complex molecule is called a polypeptide.
A peptide bond can undergo hydrolysis. This breaks the peptide bond and separates the two amino acids. Although the process is very slow, hydrolysis can occur in the presence of water.
Similarities Between Glycosidic Bonding and Peptide Bonding
- Both the glycosidic bond and the peptide bond are types of covalent bonds.
- Both types of bonds are formed through condensation reactions.
- Both types can be split off by hydrolysis.
- Both types of bonds can link two entities together.
Difference between glycosidic bond and peptide bond
definition
Glycosidic bond: The glycosidic bond is a type of covalent bond that is formed between two monosaccharides.
Peptide bond: Peptide bond is a type of covalent bond that is formed between two amino acids.
Appear
Glycosidic bonds: Glycosidic bonds are present in carbohydrates / sugars.
Peptide bond: Peptide bonds are present in proteins.
Chemical bond
Glycosidic bond: The glycosidic bond can be specified as –COC-.
Peptide bond: The peptide bond can be expressed as -CONH-.
hydrolysis
Glycosidic bond: The hydrolysis of the glycosidic bond forms two monosaccharides.
Peptide bond: The hydrolysis of the peptide bond forms two amino acids.
diploma
Both glycosidic bonds and peptide bonds are types of covalent bonds. Glycosidic bonds can be found in carbohydrates. Peptide bonds can be found in proteins. The main difference between a glycosidic bond and a peptide bond is that a glycosidic bond is formed when two carbon atoms of two different monosaccharides are linked together, while a peptide bond is formed when a carbon atom of one amino acid is linked to a nitrogen atom of another amino acid.
References:
1. "Glycosidic Bond: Definition and Formation." Study.com. Study.com and Web. Available here. August 08, 2017. 2. "Peptide Binding". Wikipedia. Wikimedia Foundation, August 07, 2017. Web. Available here . 08/08/2017.
Image courtesy:
1. "Figure 03 02 04" By CNX OpenStax - (CC BY 4.0) via Commons Wikimedia 2. "Glykogen glycosidic bond" By Glykogen.svg: NEUROtikerderivative work: Marek M (Talk) - Glykogen.svg (Public Domain) via Commons Wikimedia 3. "224 Peptide Bond-01" From OpenStax College - Anatomy & Physiology, Connexions website . June 19, 2013. (CC BY 3.0) via Commons Wikimedia
