[Plasma proteomic analysis of diabetes improvement by vitamin D supplementation].

OBJECTIVE: To analyze the effect of vitamin D supplementation on the improvement of diabetes mellitus based on plasma proteomics. METHODS: Five-week-old SPF spontaneously obese rats with type 2 diabetes were randomly divided into a diabetic group and a diabetic vitamin D intervention group, and the control group was Zucker lean rats. The fasting blood glucose of the rats in each group was compared with that of the diabetic vitamin D group, and the plasma proteins of the rats in each group were compared by quantitative analysis of the high-resolution mass spectrometry system iTRAQ, and KEGG signaling pathway analysis was performed. RESULTS: The fasting blood glucose of rats in the diabetic vitamin D intervention group was significantly lower than that of the diabetic group, and the proteins that were differentially expressed in the diabetic vitamin D intervention group were significantly improved. KEGG signaling pathway analysis revealed that the differential proteins in the diabetic group were mainly distributed among enzymes, exosomal proteins, and peptidases and inhibitors, and that the number of differences in these three classes of proteins was significantly reduced in the diabetic intervention group. CONCLUSION: Vitamin D supplementation can improve the differential expression of fasting glucose and plasma proteins in the diabetic rats.

Binding mechanism of lipase to Ligupurpuroside B extracted from Ku-Ding tea as studied by multi-spectroscopic and molecular docking methods.

The interaction of lipase with Ligupurpuroside B was studied by multiple spectroscopic techniques, enzyme activity and molecular modeling under simulative physiological condition. According to Stern-Volmer equation, fluorescence of lipase was quenched by Ligupurpuroside B via a static quenching mechanism because of formation of Ligupurpuroside B-lipase complex. Binding constants, number of binding sites & thermodynamic parameters were evaluated. The values of ΔGo (-25.085 kJ mol-1), ΔHo (-12.14 kJ mol-1) and ΔSo (+43.45 J mol-1 K-1) at 298 K indicated that Ligupurpuroside B-lipase interaction is spontaneous and hydrophobic interaction is the main force stabilizing the Ligupurpuroside B-lipase complex. The enzyme activity assay showed that Ligupurpuroside B inhibited lipase activity efficiently. Synchronous fluorescence spectra (SFS) suggested that Ligupurpuroside B is closer to Trp residues than to Tyr residues. All above experimental results were confirmed by molecular docking studies, which further indicated the binding site of Ligupurpuroside B on the surface of lipase, and the amino acid residues of lipase interacting with Ligupurpuroside B. Our present research work gives valuable information on the design of drugs with lipase as a carrier and should be useful for food industries.