Arabinotetraose is a linear tetrasaccharide composed of four α-L-arabinofuranose units linked by (1→5) glycosidic bonds, with the molecular formula C₂₀H₃₄O₁₇ and a molecular weight of 546.5 Da. It exhibits high purity (>95%) in powder form and functions as a specialized substrate for endo-arabinanase enzymes in biochemical assays.

Biological Sources and Occurrence

Arabinotetraose originates from the enzymatic hydrolysis of arabinan polysaccharides, key components of plant cell walls within pectic structures such as rhamnogalacturonan I. These polysaccharides are often decorated with α-1,2- or α-1,3-L-arabinofuranose side chains. Arabinotetraose also appears in degradation products of arabinoxylan and other hemicelluloses, influencing microbial utilization in gut ecosystems.

Enzymatic Degradation and Metabolism

Endo-arabinanases hydrolyze arabinotetraose into shorter arabinooligosaccharides such as arabinotriose and arabinobiose. In parallel, α-L-arabinofuranosidases like CjAbf43A target specific O2- or O3-linked substitutions on the backbone. In bacteria such as Bacteroides ovatus, the degradation of arabinotetraose supports selective growth and contributes to short-chain fatty acid production through fermentation.

Research Applications

Arabinotetraose enables precise assays for arabinan-degrading enzymes and supports structural studies of glycoside hydrolase family 43 members using crystallography and NMR. It is also used to analyze arabinose distribution in xylooligosaccharides for prebiotic development and to optimize biomass conversion processes. High-purity standards of arabinotetraose facilitate tandem mass spectrometry for linkage determination and functional food metabolite profiling.