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Zheng J, Li Y, Zhao S, Dong G, Yi S, Li X. Inhibition effect of epicatechin gallate on acid phosphatases from rainbow trout (Oncorhynchus mykiss) liver by multispectral and molecular docking. Int J Biol Macromol 2024; 261:129794. [PMID: 38296148 DOI: 10.1016/j.ijbiomac.2024.129794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/06/2024]
Abstract
Inhibition of acid phosphatase, which significantly contributes to inosine 5'-monophosphate (IMP) degradation, is crucial for preventing flavor deterioration of aquatic products during storage. In this study, the inhibitory effect of epicatechin gallate (ECG) on the activity of acid phosphatase isozymes (ACPI and ACPII) was analyzed using inhibition kinetics, fluorescence spectroscopy, isothermal titration calorimetry, and molecular simulation. ACPI and ACPII with molecular weights of 59.5 and 37.3 kDa, respectively, were purified from rainbow trout liver. ECG reversibly inhibited ACPI and ACPII activities via mixed-type inhibition, with half maximal inhibitory concentration (IC50) of 0.24 ± 0.01 mmol/L and 0.27 ± 0.03 mmol/L, respectively. Fluorescence spectra indicated that ECG statically quenched the intrinsic fluorescence of ACPI and ACPII. ECG could spontaneously bind to ACPI and ACPII through hydrogen bonding and van der Waals forces and exhibited a higher affinity for ACPI than for ACPII. In addition, molecular dynamic simulation revealed that ECG-ACPI and ECG-ACPII complexes were relatively stable during the entire simulation process. Our findings provide a theoretical basis for the use of ECG as an inhibitor of ACP to improve the flavor of aquatic products.
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Affiliation(s)
- Jie Zheng
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China
| | - Yingchang Li
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China; Institute of Ocean Research of Bohai University, Jinzhou 121013, China.
| | - Songmin Zhao
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China
| | - Gaoyuan Dong
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China
| | - Shumin Yi
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China; Institute of Ocean Research of Bohai University, Jinzhou 121013, China
| | - Xuepeng Li
- College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China; Institute of Ocean Research of Bohai University, Jinzhou 121013, China.
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Sun J, Wang X, Nie Z, Ma L, Sai H, Cheng J, Liu Y, Duan J. Characterization of the interactions between Fulvic acid and Trypsin with Spectroscopic and Molecular Docking technology. Chem Biodivers 2024; 21:e202301366. [PMID: 38073179 DOI: 10.1002/cbdv.202301366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/10/2023] [Indexed: 01/13/2024]
Abstract
The interaction mechanism between trypsin and fulvic acid was analyzed by multispectral method and molecular docking simulation. The fluorescence spectra showed that fulvic acid induced static quenching of trypsin. The validity of this conclusion was further substantiated through the computation of the binding constants. The thermodynamic parameters show that the reaction is mainly controlled by van der Waals force and hydrogen bond force, and the reaction is spontaneous. In addition, based on the obtained binding distance, there may be a non-radiative energy transfer between the two. The ultraviolet spectrum showed that fulvic acid could shift the absorption peak of trypsin, indicating that fulvic acid had an effect on the secondary structure of trypsin. According to the synchronous fluorescence spectrum results, fulvic acid primarily interacts with tryptophan residues in trypsin and induces alterations in their microenvironment. Three-dimensional fluorescence spectrum and circular dichroism further proves this conclusion. The molecular docking simulation reveals that the interaction between the two groups primarily arises from hydrogen bonding and van der Waals forces. The findings suggest that FA has the ability to induce conformational changes in trypsin's secondary structure.
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Affiliation(s)
- Jisheng Sun
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
| | - Xiaoxia Wang
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
- Innermongolia Engineering Research Center of Comprehensive Utilization of Bio-coal Chemical Industry, Baotou, 014010, China
| | - Zhihua Nie
- School of life sciences, Tsinghua University, Beijing, 100084, China
| | - Litong Ma
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
- Innermongolia Engineering Research Center of Comprehensive Utilization of Bio-coal Chemical Industry, Baotou, 014010, China
| | - Huazheng Sai
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
| | - Jianguo Cheng
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
| | - Yunying Liu
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
| | - Jianguo Duan
- School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou, 014010, China
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Vutharadhi S, Ranganatha KS, Nadimpalli SK. Momordica charantia seed proteins - Purification, biochemical characterization of a class II α-mannosidase isoenzyme and its interaction with the lectin and protein body membrane. Int J Biol Macromol 2023; 248:126022. [PMID: 37506790 DOI: 10.1016/j.ijbiomac.2023.126022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/05/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Momordica charantia seeds contain a galactose specific lectin and mixture of glycosidases. These bind to lectin-affigel at pH 5.0 and are all eluted at pH 8.0. From the mixture, α-mannosidase was separated by gel filtration (purified enzyme Mr ∼ 238 kDa). In native PAGE (silver staining) it showed three bands that stained with methylumbelliferyl substrate (possible isoforms). Ion exchange chromatography separated two isoforms in 0.5 M eluates and one isoform in 1.0 M eluate. In SDS-PAGE it dissociated to Mr ∼70 and 45 kDa subunits, showing antigenic similarity to jack bean enzyme. MALDI analysis confirmed the 70 kDa band to be α-mannosidase with sequence identity to the genomic sequence of Momordica charantia enzyme (score 83, 29 % sequence coverage). The pH, temperature optima were 5.0 and 60o C respectively. Kinetic parameters KM and Vmax estimated with p-nitrophenyl α-mannopyranoside were 0.85 mM and 12.1 U/mg respectively. Swainsonine inhibits the enzyme activity (IC50 value was 50 nM). Secondary structural analysis at far UV (190-300 nm) showed 11.6 % α-helix and 36.5 % β-sheets. 2.197 mg of the enzyme was found to interact with 3.75 mg of protein body membrane at pH 5.0 and not at pH 8.0 suggesting a pH dependent interaction.
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Affiliation(s)
- Shivaranjani Vutharadhi
- Protein Biochemistry and Glycobiology Laboratory, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Kavyashree Sakharayapatna Ranganatha
- Protein Biochemistry and Glycobiology Laboratory, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Siva Kumar Nadimpalli
- Protein Biochemistry and Glycobiology Laboratory, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India.
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