Bacterial azoreductase (AzR) (AzR)

Bacterial azoreductases are a diverse group of enzymes produced by various species of the human gut microbiota, including Bacteroides, Clostridium, and Enterococcus, which play a critical role in the metabolism of xenobiotics containing azo groups (PubMed: 20653514). These enzymes utilize NAD(P)H as an electron donor and typically require flavin mononucleotide (FMN) as a cofactor to catalyze the reductive cleavage of azo linkages into primary amines. In clinical pharmacology, bacterial azoreductases are exploited as a target for colon-specific drug delivery, particularly for treating inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease (PubMed: 16153165). Prodrugs like sulfasalazine and balsalazide are designed with azo bonds that remain intact during transit through the upper gastrointestinal tract but are cleaved by these bacterial enzymes upon reaching the large intestine. This localized activation releases the active anti-inflammatory moiety, 5-aminosalicylic acid (5-ASA), directly at the site of disease, thereby maximizing therapeutic efficacy while minimizing systemic absorption and side effects (PubChem: CID 5339). However, the therapeutic performance of these prodrugs can be significantly influenced by the composition and metabolic activity of an individual's microbiome, which may be altered by diet, age, or the use of broad-spectrum antibiotics (PubMed: 22435347).

Other names

Azo reductaseFMN-dependent azoreductaseNAD(P)H:azoreductaseAzo-dye oxidoreductaseNAD(P)H:azo-dye oxidoreductase

Reductive cleavage of the azo linkage (-N=N-) in prodrugs, releasing active therapeutic moieties specifically in the colon where bacterial density is high.