Spectroscopic characterisation of interaction of ferulic acid with aldehyde dehydrogenase (ALDH)

Insight into the binding characteristics of epigallocatechin-3-O-gallate and alcohol dehydrogenase: Based on the spectroscopic and molecular docking analysis

Alcohol dehydrogenase (ADH) is one of the pivotal enzymes for alcohol metabolism, which plays an important role in many physiological processes. In this study, the activation effects of epigallocatechin-3-O-gallate (EGCG) on ADH and the characteristics of the interaction were investigated via biochemical method, spectroscopy methods, and molecular docking. The results demonstrated that EGCG significantly increased the catalytic activity of ADH with a 33.33% activation rate and that EGCG blending slightly altered the microenvironment surrounding ADH aromatic amino acids, with an increase in the quantity of β-sheet and a decrease in the α-helix. Through the thermal stability analysis, it is further shown that the interaction of the two affects the intra-molecular hydrogen bond formation of the protein, and the conformation is partially extended. Besides, a total of 8 residues in ADH participated in the docking with EGCG, among which Asp-227, Lys-231, Glu-234, Gly-365 and Glu-366 participated in the formation of hydrogen bonds. At the same time, EGCG and amino group of Lys-231 form a noncovalent bond through cation-π interaction. In particular, hydrogen bonding was beneficial to keep the stability of EGCG-ADH, which was the primary driver of ADH activity activation. The results supply a new way for EGCG to activate ADH and a theoretical basis for the development of anti-alcoholism products.

Insights into the interaction of cyclooxygenase and lipoxygenase with natural compound 3,4',5,7-Tetrahydroxyflavone based on multi-spectroscopic and metabolomics

Hypoxia induce right ventricular dysfunction in human heart, but the molecular mechanism remains limited. As known, cyclooxygenases (COX) and lipoxygenases (LOX) play a key role in the cardiovascular system under hypoxia. 3,4',5,7-Tetrahydroxyflavone (THF), which widely exists in a variety of plants and vegetables, is famous for good ability to relieve cardiac injury, but the mechanism remains to be further understood. In this study, we firstly estimated the preventive role of THF against hypoxia-induced right ventricular dysfunction. Metabolomics analysis showed there were differential metabolites involved in above process, which helped us to screen the crucial regulated enzymes of these metabolites. Molecular docking and multi-spectroscopic revealed the molecular mechanism of interaction between THF and COX/LOX. Results suggested that THF bound to COX/LOX through static quenching and these bindings were driven by hydrogen bonds. After binding with THF, the secondary structure of COX/LOX was changed. In general, this study indicated that THF inhibited COX/LOX by spontaneously forming complexes with them.

Insight into the binding characteristics of rutin and alcohol dehydrogenase: Based on the biochemical method, spectroscopic experimental and molecular model

Alcohol dehydrogenase (ADH) is a crucial enzyme in the alcohol metabolism pathway. Its activity is associated with the development of alcohol-relative diseases. Rutin is a kind of widely distributed dietary flavonoids, which have the ability to resist alcohol-induced liver injury. Here, the role of rutin on alcohol metabolism was investigated via the methods of biochemistry, spectroscopy and computer simulation. The experiment results demonstrated that rutin entered into the position of coenzyme (NAD) on ADH and formed a binary complex, which of process activated the catalyze activity of ADH in a concentration dependent manner. The combination of rutin on ADH induced microenvironmental variations as well as secondary structural change of ADH, where the level of α-helix reduced yet β-sheet raised. The values of ∆H and ∆S suggested that H-bonds and van der Waals force occupied vital roles in the stabilization of ADH-rutin complex. Furthermore, molecular docking results further confirmed that the H-bonds between the hydroxyl groups on the benzene rings of rutin and surrounding amino acid were beneficial to maintain the stability of complex. Particularly, the van der Waals force and π-alkyl between rutin and Val residues may be the main reason for activation of ADH activity.