What is the Difference Between Globoside and Ganglioside

The key difference between globoside and ganglioside is that globosides are neutral in the presence of sugars, while gangliosides have a net negative charge at acidic pH due to the presence of sialic acids.

Glycosphingolipids are a class of glycolipids and consist of a ceramide backbone that link by a β-glycosidic bond to complex glycans. They are found in eukaryotes and are vital to multi-cellular organisms. Glycosphingolipids help to modulate membrane-protein function, regulate cell growth and differentiation and also play an important role in neoplastic transformation through cell-to-cell communication. They also participate in possible interactions with receptors and signalling systems and help to develop immune cells in the body. Globoside and ganglioside are two complex but essential glycosphingolipids present in eukaryotes.

CONTENTS

1. Overview and Key Difference
2. What is Globoside 
3. What is Ganglioside
4. Similarities – Globoside and Ganglioside
5. Globoside vs Ganglioside in Tabular Form
6. Summary – Globoside vs Ganglioside

What is Globoside?

Globoside is a type of glycosphingolipid that consists of more than one sugar as the side chain of the ceramide backbone. This backbone links to a neutral oligosaccharide head group, and the name globoside lipid class reflects the number of sugars in this group. The ceramide backbone contains a hydrocarbon chain with the name long-chain base and contains one fatty acid chain that links to the ceramide. The sugars are a combination of N-acetylgalactosamine, D-glucose, or D-galactose. The side chain has a possibility to cleave by galactosidases and glucosidases. Globosides are usually present in eukaryotes.

The main function is to serve as an important component of the cell membrane where the sugar group faces the extracellular space. This also provides the cell with a coating of carbohydrates. Globosides interact with hormones and receptors of the signal transduction mechanism. Therefore, it helps to regulate cellular signalling pathways in many ways. The most common globosides present in mammals are Gb3 and Gb4. Gb3 accumulations and deficiency of α-galactosidase A cause Fabry’s disease. It is an inherited metabolic disease. Gb3 also links with apoptosis and programmed cell death. The major role of Gb4 is the determination of blood type since each blood group antigen stems from Gb4. Gb4 also plays a post-entry role in productive infections since it is known as the receptor for Parvovirus B19.

What is Ganglioside?

Ganglioside is a molecule that consists of a glycosphingolipid with one or more sialic acids linking to the sugar chain. Ganglioside comprises a ceramide lipid tail attached to a glycosidic linkage to a glycan head-group which contains one or more sialic acid residues. Examples of sialic acids are n-acetylneuraminic acid and NANA. Due to the presence of sialic acids, gangliosides have a net negative charge at acidic pH. NeuNAc, which is an acetylated derivative of the carbohydrate sialic acids, makes the head group of gangliosides.

Gangliosides are present on cell surfaces with two hydrocarbon chains of the ceramide in the plasma membrane and oligosaccharides on the extracellular surface. Gangliosides are predominantly found in the nervous system. The oligosaccharide groups on gangliosides act as surface markers which serve as specific determinants in cellular recognition and cell to cell communication. When serving as a specific determinant, gangliosides play a role in the growth and differentiation of tissues as well as carcinogenesis. The carbohydrate head groups act as specific receptors for some pituitary glycoprotein hormones and some bacterial protein toxins. Common gangliosides present in humans are GM1, GM2, GM3, GD1a, GD1b, GD2, GD3, GT1b, GT3 and GQ1.

What are the Similarities Between Globoside and Ganglioside?

• Globoside and ganglioside are glycosphingolipids.
• Moreover, both are composed of carbon, hydrogen, and oxygen.
• Both contain a ceramide backbone and oligosaccharide fragments.
• They are abundant in nerve endings and specific hormone receptors sites on cell surfaces.
• Both play an important role in molecular recognition.
• They are present in eukaryotes.

What is the Difference Between Globoside and Ganglioside?

Globosides are neutral in the presence of sugars, while gangliosides have a net negative charge at acidic pH due to the presence of sialic acids. Thus, this is the key difference between globoside and ganglioside. Moreover, globosides consist of two or more sugars, usually d-glucose, d-galactose, or N-acetyl-d-galactosamine, while gangliosides consist of two or more sialic acids such as N-acetylneuraminic acid and NANA. Hence, this is another difference between globoside and ganglioside. Globosides are widely found in the membrane. Gangliosides usually make up about 6% of gray matter in the brain and contain various types.

The below infographic presents the differences between globoside and ganglioside in tabular form for side by side comparison.

Summary – Globoside vs Ganglioside

Globosides are neutral in the presence of sugars. In contrast, gangliosides have a net negative charge at acidic pH due to the presence of sialic acids. A globoside is a type of glycosphingolipid containing more than one sugar as the side chain of the ceramide backbone. The sugars are a combination of N-acetylgalactosamine, D-glucose, or D-galactose. A ganglioside is a molecule containing a glycosphingolipid with one or more sialic acids linking on the sugar chain. So, this summarizes the difference between globoside and ganglioside.

Reference:

1. Christie, William (Bill) W. “Gangliosides.” Lipidmaps.
2. “Globosides Analysis – Lipid Analysis.” Lipotype GmbH.

Image Courtesy:

1. “Acetylgalactosamine” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia
2. “Structure of GM1, GM2, GM3” By LHcheM – Own work (CC BY-SA 3.0) via Commons Wikimedia