Pyridoxine 5′-phosphate oxidase (PNPO)

Pyridoxine 5′-phosphate oxidase is a homodimeric FMN-dependent oxidoreductase that completes the biosynthesis of pyridoxal 5′-phosphate, the active vitamin B6 cofactor essential for amino acid metabolism, neurotransmitter synthesis, and cellular function. Its activity is highest in the liver and is tightly regulated by substrate availability and allosteric inhibition by its product, PLP. Mutations in the PNPO gene can result in a deficiency syndrome, primarily causing early-onset, treatment-responsive epileptic seizures. Recent research implicates PNPO as a potential therapeutic target in some cancers, where its expression affects cell cycle, apoptosis, and invasiveness. If more structured biochemical, clinical, or pharmacological details are needed, the PNPO gene is well characterized in public databases, and its role as a drug target in diseases like epilepsy and cancer is an active area of research.

Other names

Pyridoxamine-phosphate oxidasePyridoxine/pyridoxamine 5′-phosphate oxidasePyridoxal 5′-phosphate synthasePNP/PMP oxidaseHEL-S-302PDXPO

Drugs may act by regulating the enzymatic activity (e.g., by inhibiting regulatory pathways such as TGF-β for cancer). PLP acts as an allosteric inhibitor of PNPO. Vitamin B6 analogues and supplements provide PLP directly (in deficiency disorders).