Interaction-based screening, Monte Carlo Bayesian inference-based de novo design and in vitro verification of adenine-binding peptide.

One of the main reasons for hyperuricemia is high purine intake. The primary strategy for treating hyperuricemia is blocking the purine metabolism enzyme. However, by binding the purine bases directly, we suggested a unique therapeutic strategy that might interfere with purine metabolism. There have been numerous reports of extensive interactions between proteins and purine bases. Adenine, constituting numerous protein co-factors, can interact with the adenine-binding motif. Using Bayesian Inference and Markov chain Monte Carlo sampling, we created a novel adenine-binding peptide Ile-Tyr-Val-Thr based on the structure of the adenine-binding motifs. Ile-Tyr-Val-Thr generates a semi-pocket that can clip the adenine within, as demonstrated by docking. Then, using thermodynamic techniques, the interaction between Ile-Tyr-Val-Thr and adenine was confirmed. The KD value is 1.50e-5 (ΔH = -20.2 kJ/mol and ΔG = -27.6 kJ/mol), indicating the high affinity. In brief, the adenine-binding peptide Ile-Tyr-Val-Thr may help lower uric acid level by blocking the absorption of food-derived adenine.

Intestinal absorptivity-increasing effects of sodium N-[8-(2-hydroxybenzoyl)amino]-caprylate on food-derived bioactive peptide.

Delivering bioactive peptides orally is hampered by poor absorption across the gastrointestinal barrier. Using the walnut-derived peptide PW5, PPKNW, we explored whether coformulation of peptides with absorption enhancer sodium N-[8-(2-hydroxybenzoyl)aminocaprylate] (SNAC) could improve the intestinal absorption of orally-administered bioactive peptides. Herein, the application of SNAC enhanced the absorption efficiency of PW5 in a non-everted gut sac model. Particle size distribution (1 027.8 ± 6.74 nm) and zeta potential (-2.89 ± 0.07 mV) of the PW5-SNAC complex were significantly greater than that of individual PW5 and SNAC. Scanning electron microscopy revealed that SNAC application could aggravate the surface roughness and reduce the compact structure of PW5. It further showed that PW5 and SNAC binds through an endothermic process underpinned by hydrogen bond and van der Waals forces and that SNAC could bound primarily to the internal calyx of PW5. These findings are helpful for the effective delivery of bioactive peptides.

Effect on purine releasement of Lentinus edodes by different food processing techniques.

Lentinus edodes (LE) is very popular in the world and also considered as high purine food. However, few focuses on purine types and its change during food processing. Here, we first compared 3 drying techniques, including roast-drying, freeze-drying, sun-drying on purine contents of LE by using acidolysis and HPLC. It showed that adenine decreased significantly after roast-drying (120 °C), which may be caused by thermal damage of DNA. Total purine decreased significantly after freeze-drying, while roast-dried and sun-dried LE remained unchanged. The effect of moist heat (boiling) on LE purine were also evaluated. Total purine increased due to xanthine increasement (331.72 ± 50.07%). And purine contents transferred into boiled liquid was higher than that in boiled solid. Compared with sun-dry and roast-dry processing, freeze-drying could notably affect the purine release from LE and decrease purine contents. Therefore, freeze-drying is recommended for process techniques for hyperuricemia and gouts populations.