Trehalose

Definition

A non-reducing disaccharide composed of two α-glucose units linked by a 1,1-glycosidic bond, serving as the primary blood sugar and cryoprotectant in insects and many other invertebrates. In arthropods, trehalose circulates in hemolymph at high concentrations (often 20–50 mM) and protects tissues from damage during freezing, desiccation, and thermal stress by stabilizing proteins and membranes. It is synthesized from glycogen or dietary glucose via the trehalose-6-phosphate synthase pathway and is metabolized to fuel flight and other energy-demanding activities.

Etymology

From trehala, the name of the cocoon-like nests of certain Middle Eastern beetles (Larinus spp.) from which the sugar was first isolated in the 19th century.

Example

Overwintering larvae of the goldenrod gall fly (Eurosta solidaginis) accumulate trehalose to concentrations exceeding 500 mM, enabling survival at temperatures below −20°C by preventing ice crystal formation and membrane damage.

Synonyms

• mycose

Related Terms

• cryoprotectant
• anhydrobiosis
• Hemolymph
• Glycogen
• glucose
• disaccharide
• Chitin
• cold hardiness
• Diapause

Usage Notes

Distinguished from glucose (the monomer unit) and from other disaccharides such as sucrose (glucose–fructose, α1→β2) and maltose (glucose–glucose, α1→4). The α,α-1,1 linkage of trehalose confers exceptional chemical stability and non-reducing properties, making it ideal for long-term energy storage and stress protection. In entomological literature, 'trehalose' often refers specifically to the predominant α,α-isomer; the stereoisomers neotrehalose (α,β) and isotrehalose (β,β) are not known from natural biological systems.