Mannans

Mannans

Mannans are a type of polysaccharide that are primarily composed of the sugar mannose. They are found in the cell walls of yeasts, fungi, and plants, and play a crucial role in various biological processes. This article provides a comprehensive overview of mannans, their structure, function, and significance in different organisms.

Structure

Mannans are polysaccharides that consist of mannose units linked together by glycosidic bonds. The most common type of linkage in mannans is the β(1→4) linkage, although other linkages such as α(1→6) can also occur. The structure of mannans can vary significantly depending on the source organism, leading to differences in their physical and chemical properties.

Types of Mannans

• Linear Mannans: These are composed of a straight chain of mannose units. They are typically found in the cell walls of certain plants and algae.
• Galactomannans: These are mannans that have galactose residues attached to the mannose backbone. They are commonly found in the seeds of legumes such as guar and locust bean.
• Glucomannans: These contain both glucose and mannose units. They are found in the cell walls of some plants and fungi.

Biological Functions

Mannans serve various functions in different organisms:

• In Plants: Mannans are a component of the hemicellulose fraction of plant cell walls. They contribute to the structural integrity and rigidity of the cell wall, and play a role in cell growth and development.
• In Fungi and Yeasts: Mannans are a major component of the cell wall, where they are involved in maintaining cell shape, protecting against environmental stress, and mediating cell-cell interactions.
• In Animals: While animals do not produce mannans, they can interact with mannans through their immune system. Mannans can act as antigens and are recognized by pattern recognition receptors such as mannose-binding lectin, which plays a role in the innate immune response.

Industrial and Medical Applications

Mannans have several applications in industry and medicine:

• Food Industry: Galactomannans are used as thickening agents and stabilizers in food products. For example, guar gum and locust bean gum are used to improve the texture and consistency of ice creams and sauces.
• Pharmaceuticals: Mannans are used in drug delivery systems due to their biocompatibility and ability to form gels. They are also being studied for their potential to enhance the immune response in vaccines.
• Biotechnology: Mannans are used in the production of biofuels and biodegradable plastics. They are also used in the fermentation industry as a carbon source for microbial growth.

Also see

• Polysaccharides
• Hemicellulose
• Glycosidic bond
• Guar gum
• Locust bean gum
• Mannose