Flavin adenine dinucleotide synthetase 1 (FLAD1)

Flavin adenine dinucleotide synthetase 1 (FLAD1) is a human enzyme that catalyzes the *adenylylation* of FMN to produce FAD, a critical redox cofactor utilized in numerous cellular oxidation-reduction reactions[1][2][3][4][9]. This bifunctional, multi-domain enzyme contains a PAPS reductase domain responsible for FAD synthesis, and in some isoforms, a molybdopterin-binding domain with hydrolytic activity[1][2]. Genetic defects in FLAD1 can cause metabolic diseases by reducing FAD levels and impairing FAD-dependent mitochondrial metabolism[3][4][5]. FLAD1 is essential in the metabolic pathway for water-soluble vitamins and cofactor biosynthesis[3][4][9]. While no direct pharmacological inhibitors or activators are available, riboflavin supplementation can ameliorate symptoms in patients with partial deficiency[3]. FLAD1 is an important enzyme target in inherited metabolic diseases, and its activity is central to cellular energy metabolism through FAD production.

Other names

FAD synthaseFAD synthase regionFAD pyrophosphorylaseFMN adenylyltransferaseFlavin adenine dinucleotide synthaseFAD-adenylyl transferaseFADSLSMFLADFad1FAD1PP591Flavin adenine dinucleotide synthetase homolog

Riboflavin supplementation increases substrate availability for FLAD1-mediated FAD biosynthesis, compensating for partial enzyme deficiency. The enzyme mechanism is adenylyltransfer—transfers AMP from ATP to FMN forming FAD.