The key difference between fucose and rhamnose is that fucose is an aldohexose present in several glycans and mucopolysaccharides, whereas rhamnose is a methyl pentose that occurs in leaves and flowers of poison ivy and also as a constituent of many plant glycosides.
Fucose and rhamnose are deoxy sugars sharing the same chemical formula, but they have different chemical structures that represent different properties.
CONTENTS
1. Overview and Key Difference
2. What is Fucose
3. What is Rhamnose
4. Fucose vs Rhamnose in Tabular Form
5. Summary – Fucose vs Rhamnose
What is Fucose?
Fucose is a hexose deoxy sugar having the chemical formula C6H12O5. We can find this compound on N-linked glycans on the mammalian, insect, and plant cell surfaces. This sugar can be described as the fundamental sub-unit of the seaweed polysaccharide fucoidan.
Figure 01: The Chemical Structure of Fucose
There are two major differences between fucose and other six-membered carbon sugars in mammals: the lack of a hydroxyl group on the carbon at position 6 and the L-configuration. This substance is equivalent to 6-deoxy-L-galactose.
The glycan structures consisting of fucose units are known as fucosylated glycans. In these structures, fucose can exit as a terminal modification or serve as an attachment that can point to adding other sugars. The human body has N-linked glycans. There, fucose can be observed linking alpha-1,6 to the terminal beta-N-acetylglucosamine. The fucose units existing in non-reducing terminals link alpha-1.2 to galactose, forming an H antigen, which is the substructure of the A and B blood group antigens.
Moreover, fucose is released from fucose-containing polymers via an enzyme named alpha-fucosidase that can be found in lysosomes. In addition, L-fucose shows several potential applications in cosmetics, pharmaceuticals, and dietary supplements.
What is Rhamnose?
Rhamnose or rham is a naturally occurring deoxy sugar having the chemical formula C6H12O5. We can classify it as either a methyl-pentose or a 6-deoxy-hexose. Predominantly, this compound occurs in nature as L-rhamnose. Since most of the sugars that occur naturally are in the D-form, the abundance of L-rhamnose is quite unusual. However, there are L-fucose and L-arabinose in the abundant forms of their corresponding sugars as well. However, there are D-rhamnose molecules that we can observe occurring in nature, for example, in some bacterial species such as Pseudomonas aeruginosa and Helicobacter pylori.
Figure 02: The Chemical Structure of Rhamnose
The molar mass of this sugar is 164.15 g/mol. It has a density of about 1.41 g/cm3. The melting point of rhamnose can range from 91 to 93 degrees Celsius. We can isolate this substance from Buckthorn poison sumac and some plants in the genus Uncaria. Moreover, rhamnose can be produced by microalgae, which belong to the class of Bacillariophyceae.
We can commonly find rhamnose bound to other sugars. For example, it can be found glycone component of glycosides from many plants. Also, rhamnose can be found as a component of the outer cell membrane of acid-fast bacteria in the genus of Mycobacterium.
What is the Difference Between Fucose and Rhamnose?
Fucose and rhamnose share the same chemical formula but different chemical structures that represent different properties. The key difference between fucose and rhamnose is that fucose is an aldohexose present in several glycans and mucopolysaccharides, whereas rhamnose is a methyl pentose that occurs in leaves and flowers of poison ivy and also as a constituent of many plant glycosides.
Below is a summary of the difference between fucose and rhamnose in tabular form for side-by-side comparison.
Summary – Fucose vs Rhamnose
The key difference between fucose and rhamnose is that fucose is an aldohexose present in several glycans and mucopolysaccharides, whereas rhamnose is a methyl pentose that occurs in leaves and flowers of poison ivy and also as a constituent of many plant glycosides.
Reference:
1. “Rhamnose.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “L-Fucose” By Glycoform – Using chemdraw (CC BY-SA 4.0) via Commons Wikimedia
2. “Alpha-L-Rhamnopyranose” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia