A high-purine diet readily induces hyperuricemia, whereas certain lactic acid bacteria (LAB) can absorb and metabolize purines, thereby modulating uric acid levels. However, studies elucidating the molecular mechanisms by which lactic acid bacteria lower uric acid levels remain limited. In this study, we investigated Levilactobacillus brevis PDD-5, a strain previously shown to alleviate hyperuricemia through efficient purine absorption. Comprehensive metabolic and transcriptomic analyses were performed to compare L. brevis PDD-5 with a non-uric-acid-lowering strain. Using HPLC–MS/MS–based targeted metabolomics, we identified significant differences in purine nucleoside degradation between the two strains. Transcriptomic profiling revealed that L. brevis PDD-5 activates purine catabolism via upregulation of the deoD gene, which encodes purine nucleoside phosphorylase, thereby facilitating nucleoside-to-base conversion. Xanthine served as a key substrate promoting the de novo purine synthesis pathway and remained active under purine-rich conditions, likely because of transcriptional derepression of the purR regulator. These findings elucidate the molecular framework of the uric acid–lowering mechanism of L. brevis PDD-5 and provide a theoretical foundation for the development of safe, effective LAB-based interventions against hyperuricemia.

The interaction amid Monascus pigment (MP) and ovalbumin (OVA) was studied using multispectral and computer simulations. The fluorescence results demonstrated that MP could effectively quench the fluorescence emission of OVA. According to Stern-Volmer and the double logarithmic equation, the quenching reaction of MP to OVA was static quenching, which was brought on by the combination of two molecules to shape a complex. At 298 K, the conjunction constant K_a of MP and OVA was 1.045 2 × 10⁹ L/mol, and the count of conjunction sites n was 1.955 7. The thermodynamic constant of MP-OVA binding was counted according to Van’s Hoff equation, and the reaction belonged to the active process of reducing Gibbs free energy. The ultraviolet–visible (UV-Vis) absorption spectroscopy indicated an interaction between MP and OVA. The interaction force between MP and OVA and the steadiness of the conjunction were examined by using molecular docking and molecular dynamics simulation. The findings suggested that MP formed a complex with OVA via non-covalent binding, the formation and steadiness of the complex were promoted through hydrogen bonding, hydrophobic interaction, and Van der Waals force.