L-arabinose isomerase (L-AI)

L-arabinose isomerase (EC 5.3.1.4) is a microbial enzyme that catalyzes the reversible isomerization of L-arabinose to L-ribulose, a critical step in the bacterial utilization of pentose sugars (UniProt, 2024). While it is not a therapeutic target in human medicine, it is of significant industrial importance due to its ability to convert D-galactose into D-tagatose, a rare sugar used as a low-calorie sweetener (Kim, 2010). D-tagatose has a low glycemic index and potential prebiotic properties, making it relevant for the management of metabolic conditions like diabetes and obesity (Zhang et al., 2021). The enzyme typically functions as a hexamer and requires divalent metal ions, such as manganese or cobalt, for its catalytic activity and structural stability (Manjisetty & Chance, 2002). Because L-arabinose isomerase is absent in humans and does not participate in human physiological pathways, it is not targeted by any pharmaceutical drugs (Zhang et al., 2021). Its primary application remains in the biocatalytic production of functional foods rather than clinical therapeutics.

Other names

L-arabinose ketol-isomeraseAraA

Catalyzes the reversible isomerization of L-arabinose to L-ribulose and D-galactose to D-tagatose via a metal-dependent enediol intermediate mechanism (Manjisetty & Chance, 2002).