Kinetic Dissection of the Reaction of Human GDP-l-Fucose Synthase.

ABSTRACT: GDP-l-fucose is a universal sugar donor for the cellular biosynthesis of l-fucose-containing glycans. Its supply comes primarily from the reaction of GDP-l-fucose synthase (GFS), also known as GDP-4″-keto-6″-deoxy-d-mannose epimerase/reductase. GFS converts GDP-4″-keto-6″-deoxy-d-mannose by epimerization at both C-3″ and C-5″ followed by NADPH-dependent reduction of the carbonyl at C-4″. Here, we report kinetic and structural characterization of human GFS with the aim of dissecting the multistep pathway of the enzymatic reaction. Kinetic isotope effects due to [3″-2H] or [5″-2H] in GDP-4″-keto-6″-deoxy-d-mannose and [4S-2H] in NADPH were masked in the steady-state rate of the wild-type enzyme, indicating that the immediate catalytic steps were not rate-limiting for the overall reaction. An

SUBMITTER: Smyshliaev D 

PROVIDER: S-EPMC12362431 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature