Molybdenum cofactor (MoCo)

Molybdenum cofactor (MoCo) is an essential prosthetic group required for the catalytic activity of several vital enzymes in humans, including sulfite oxidase, xanthine dehydrogenase/oxidase, and aldehyde oxidase. These enzymes play critical roles in metabolic processes such as the detoxification of sulfite into sulfate and the catabolism of purines into uric acid. MoCo is synthesized through a complex, multi-step biosynthetic pathway that converts guanosine triphosphate (GTP) into cyclic pyranopterin monophosphate (cPMP), then to molybdopterin, and finally incorporates a molybdenum atom. Genetic mutations in the genes encoding the enzymes of this pathway (such as MOCS1 or MOCS2) lead to Molybdenum Cofactor Deficiency (MoCD), a rare and often fatal neurodegenerative disorder. In MoCD, the lack of functional MoCo results in the loss of sulfite oxidase activity, leading to the toxic accumulation of sulfite in the brain, which causes severe seizures and rapid neurological deterioration. Therapeutic strategies, such as the administration of fosdenopterin, target this system by replacing missing biosynthetic intermediates like cPMP to restore endogenous MoCo synthesis and enzyme function.

Other names

Molybdopterin cofactorMo-cofactorCyclic pyranopterin monophosphate (cPMP) pathwayMolybdenum-dependent enzyme system

Substrate replacement therapy (providing the cPMP intermediate to bypass biosynthetic blocks and restore MoCo production)