Antihyperuricemic activity and inhibition mechanism of xanthine oxidase inhibitory peptides derived from whey protein by virtual screening

Prediction and evaluation of purine-binding peptides using integrated molecular descriptors and docking analysis

Peptides and purines frequently coexist in food systems and can form specific molecular interactions, which may influence the physicochemical properties and bioavailability of purines. However, the structural basis and binding mechanisms of these peptide-purine interactions remain poorly understood. This study established a comprehensive screening approach combining molecular docking and descriptor analysis to evaluate peptide-purine binding interaction. The analysis revealed that strong-binding peptides were likely characterized by reduced cyclic structures and aromatic rings, with elevated electron-donor groups primarily composed of N and O atoms (p < 0.0001). These electron-rich functional groups appeared to enhance the formation of hydrogen bonds, which could play a crucial role in stabilizing peptide-purine complexes. Among various dietary purines, hypoxanthine emerged as the predominant species in processed meat products, warranting particular attention. Fluorescence spectroscopy experiments validated the computational predictions, confirming that the tetrapeptide WDQW (Peptide Purine Binding Score: -3.32) formed stable complexes with hypoxanthine exhibiting static quenching characteristics, primarily driven by hydrophobic interactions and hydrogen bonding. This investigation provides fundamental insights into peptide-purine binding mechanisms and establishes a screening platform for identifying peptide sequences with enhanced purine-binding properties, which might be valuable for modulating purine bioavailability in food systems.

In silico identification and experimental validation of two types of angiotensin-converting enzyme (ACE) and xanthine oxidase (XO) milk inhibitory peptides

Bioactive peptides have received significant attention due to their natural origin, low toxicity, and targeting specificity in the past decade. This study identified highly active ACE/XO inhibitors using molecular simulation and online databases and validated their in vitro antioxidant activity and the mechanisms of molecular interactions. According to computer predictions, Asp-Gly-Gly (DGG) and Asp-Gly-Met (DGGM) were identified as potential hydrolysates of common gastrointestinal peptidases with well water-soluble, non-toxic, and non-allergenic. Fourier transform infrared spectroscopy showed that the two peptides altered the enzyme's secondary structure, decreasing α-helix content by about 13 %, along with increasing β-sheet, randam coli, and β-turns content. Molecular docking and molecular dynamics simulations showed that hydrogen bonding and electrostatic interactions caused DGG and DGGM to form stable and dense complexes with the two enzymes. This study provides a new way for economical and efficient screening of new ACE and XO inhibitory peptides from natural proteins.

Investigating the Role of Food-Derived Peptides in Hyperuricemia: From Mechanisms of Action to Structural Effects

Hyperuricemia, a disorder of purine metabolism associated with cardiovascular disease, gout, and kidney disease, can be alleviated by food-derived peptides. However, the precise mechanisms remain unclear, hindering their development. This study reviews uric acid-lowering peptides from various sources, focusing on two pathways: inhibiting uric acid production and promoting excretion. Low-molecular-weight peptides (<1000 Da) exhibited superior uric acid-lowering effects. We further explored the relationships between amino acid composition and their target interactions. Peptides rich in cyclic amino acids (tryptophan, phenylalanine, and histidine) and containing small amounts of linear amino acids (leucine, cysteine, and glycine) demonstrated significant potential for lowering uric acid. These findings provide theoretical support for developing novel functional foods for the management of hyperuricemia.

Recent Advances in the Application of Foodborne Substances in Hyperuricemia

Hyperuricemia (HUA) is a purine metabolism disorder characterized by the excessive production or inadequate excretion of uric acid. Current pharmacological strategies targeting uric acid reduction have potential adverse effects. Following the concept of "homology of medicine and food", food ingredients are increasingly being explored to prevent HUA and gout, with xanthine oxidase (XOD) emerging as a crucial therapeutic target in managing HUA. Recent scientific investigations have determined that uric acid-lowering substances come from various food sources, such as seafood, dairy products, and agricultural products. These bioactive substances have attracted wide attention because of their effective antihyperuricemia and XOD inhibitory ability. In this study, the pathogenesis, many side effects of uric acid-lowering drugs, and some components of uric acid-lowering drugs are mainly described, with emphasis on the source, composition, preparation technology, and mechanism of uric acid-lowering peptides.

Through virtual saturation mutagenesis and rational design for superior substrate conversion in engineered d-amino acid oxidase

The d-amino acid oxidase (DAAO) is pivotal in obtaining optically pure l-glufosinate (l-PPT) by converting d-glufosinate (d-PPT) to its deamination product. We screened and designed a Rasamsonia emersonii DAAO (ReDAAO), making it more suitable for oxidizing d-PPT. Using Caver 3.0, we delineated three substrate binding pockets and, via alanine scanning, identified nearby key residues. Pinpointing key residues influencing activity, we applied virtual saturation mutagenesis (VSM), and experimentally validated mutants which reduced substrate binding energy. Analysis of positive mutants revealed elongated side-chain prevalence in substrate binding pocket periphery. Although computer-aided approaches can rapidly identify advantageous mutants and guide further design, the mutations obtained in the first round may not be suitable for combination with other advantageous mutations. Therefore, each round of combination requires reasonable iteration. Employing VSM-assisted screening multiple times and after four rounds of combining mutations, we ultimately obtained a mutant, N53V/F57Q/V94R/V242R, resulting in a mutant with a 5097% increase in enzyme activity compared to the wild type. It provides valuable insights into the structural determinants of enzyme activity and introduces a novel rational design procedure.

Understanding Hyperuricemia: Pathogenesis, Potential Therapeutic Role of Bioactive Peptides, and Assessing Bioactive Peptide Advantages and Challenges

Hyperuricemia is a medical condition characterized by an elevated level of serum uric acid, closely associated with other metabolic disorders, and its global incidence rate is increasing. Increased synthesis or decreased excretion of uric acid can lead to hyperuricemia. Protein peptides from various food sources have demonstrated potential in treating hyperuricemia, including marine organisms, ovalbumin, milk, nuts, rice, legumes, mushrooms, and protein-rich processing by-products. Through in vitro experiments and the establishment of cell or animal models, it has been proven that these peptides exhibit anti-hyperuricemia biological activities by inhibiting xanthine oxidase activity, downregulating key enzymes in purine metabolism, regulating the expression level of uric acid transporters, and restoring the composition of the intestinal flora. Protein peptides derived from food offer advantages such as a wide range of sources, significant therapeutic benefits, and minimal adverse effects. However, they also face challenges in terms of commercialization. The findings of this review contribute to a better understanding of hyperuricemia and peptides with hyperuricemia-alleviating activity. Furthermore, they provide a theoretical reference for developing new functional foods suitable for individuals with hyperuricemia.