L-fucose isomerase

L-fucose isomerase is an enzyme (EC 5.3.1.25) that catalyzes the reversible isomerization of the aldose L-fucose into the ketose L-fuculose as part of the L-fucose catabolic pathway in bacteria such as *Escherichia coli*. It is a manganese-dependent enzyme, typically functioning as a homohexamer with a large, unique structure distinct from other known ketol isomerases[1][3][5]. Although closely homologous enzymes exist in other bacteria and may vary slightly in substrate specificity, the canonical catalytic activity involves migration of hydrogen atoms via an ene-diol intermediate. This enzyme is notable for its role in microbial utilization of fucose, a common sugar in host glycoproteins, and is being investigated for industrial and biotechnological applications in rare sugar synthesis[7]. It is not a current therapeutic target for human drugs and has no known direct clinical safety or biomarker applications.

Other names

L-fuculose isomerasefucI (gene)L-fucose aldose-ketose-isomeraseD-arabinose isomerase (when acting on arabinose)FcsI (in some bacterial pathway databases)

Catalyzes the reversible isomerization of L-fucose (aldose) to L-fuculose (ketose) via an ene-diol mechanism, requiring Mn2+ as a cofactor[1][5][7]\n- Can isomerize D-arabinose to D-ribulose in some species[2][4][5]