BIOSYNTHESIS OF D-GLUCARIC ACID IN MAMMALS: A FREE-RADICAL MECHANISM?

Article abstract of DOI:10.1016/S0008-6215(00)90201-5

In the presence of iron salts and hydrogen peroxide, D-glucuronic acid was converted into D-glucaric acid.The reaction was strongly inhibited by free-radical scavengers and is ascribed to the action of the hydroxyl radical.The formation of D-glucarate was dependent upon pH and occurred in the presence of some iron-complexing agents.The first product of oxidation was a lactone that was a strong inhibitor of β-D-glucuronidase and assumed to be D-glucaro-1,5-lactone.Microsomal preparations in the presence of NADPH also produced D-glucarate from D-glucuronic acid, presumably due to formation of hydrogen peroxide, and the product was an inhibitor of β-D-glucuronidase.Superoxide did not produce D-glucarate from D-glucuronate.The cytochrome P450 system is more likely than "glucuronolactone dehydrogenase" to be responsible for the production of D-glucaric acid in vivo.