JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2019
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IF 2.983
Baofang Zhang,Zilin Chen
A simple and valid method for rapid screening of cathepsin B inhibitors from traditional Chinese medicines (TCMs) was established by the combination of immobilized enzyme microreactor (IMER) and capillary electrophoresis. Cathepsin B was immobilized on the inner surface of the capillary by glutaraldehyde method. The separation of substrate and product could be finished by baseline within 3 min. The activity of the immobilized cathepsin B remained approximately 90% after 50 runs. The quantification and statistical analysis of the product peak area was used to evaluate the catalytic activity of cathepsin B. The value of Michaelis-Menten constant of cathepsin B was 0.85 mM. The half-maximal inhibitory concentration (IC 50 ) of L -trans-Epoxysuccinyl-leucylamido(4-guanidino)butane (E-64) was measured as 36.08 nM, which indicated that the cathepsin B reactor was successfully developed and was feasible for inhibitorscreening. The raised method was then applied to discover the inhibitory potential of 17 standard compounds from traditional Chinese medicines. Five natural products, including kaempferol, rutaecarpine, evodiamine, theophylline, lycobetaine showed potential inhibition for cathepsin B. Additionally, molecular docking study was investigated for supporting the interaction between enzyme and inhibitors.
研究领域:
药理学
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生物化学
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药物化学
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酶学
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DOI
PubMed
高影响因子
ULTRASONICS SONOCHEMISTRY
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2025
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IF 9.7
Xia Gao,Meng Gui,Shengjun Chen,Xiao Hu,Juan You,Tao Yin,Yang Hu,Shanbai Xiong,Ru Liu
Previous studies have demonstrated that high-intensity ultrasound (HIU) could enhance the gel properties of salt-reduced (1.5 % NaCl) surimi gels. Understanding its mechanism, particularly the role of key endogenous enzymes, is essential for HIU-assisted modulation of salt-reduced surimi gels with satisfactory textural properties. In this study, enzyme-specific additives were employed to investigate the enhancement effect of HIU on the gelation properties of salt-reduced (1.5 % NaCl) surimi in terms of puncture properties, protein degradation and crosslinking, dynamic rheological properties, water distribution and microstructures. Results showed that CaCl 2 and E-64 significantly increased the breaking force of surimi gels. This improvement occurred because Ca 2+ activated endogenous transglutaminase (eTGase), as evidenced by the increased formation of non-disulfide covalent bonds, while E-64 reduced protein degradation by inhibiting cysteine protease. The combination of HIU and CaCl 2 lowered the setting temperature during heating and facilitated the formation of non-disulfide covalent bonds, contributing to a three-dimensional gel network that effectively trapped more water. Consequently, the puncture properties were improved. The combination of HIU and E-64 effectively inhibited protein degradation, as evidenced by decreased TCA-soluble peptides and increased G′ at the end of the modori stage. Notably, although the combination of HIU and NH 4 Cl improved the gel properties, it still failed to form the typical three-dimensional gel network. Collectively, HIU enhanced the gelation properties of surimi through dual mechanisms of eTGase activation and cysteine protease inhibition, with eTGase activation contributing more substantially than protease inhibition, providing a theoretical foundation for HIU-assisted production of salt-reduced surimi gels.
研究领域:
食品科学
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食品化学
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生物技术
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应用物理学
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高分子科学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2024
·Vol. 59
·期 4
·2659-2666
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IF 2.6
Jiandong Shen,Bijiang Zhong,Wenshui Xia,Yanshun Xu
Summary Textural deterioration is a severe problem in fish industry. In order to study the role of structural proteins in refrigerated grass carp, myofibrillar proteins and collagen degradation were investigated at different stages. Results revealed that connective tissues of fish muscle disintegrated from day 1, failing to hold muscle myotomes together, with a decrease of shear force. Meanwhile, collagen solubility increased from day 1 and degradation of nebulin was observed after 3 days, while there was no obvious change in the bands of myosin heavy chain and actin. Furthermore, Pearson coefficient analysis revealed that insoluble collagen (ISC) and nebulin were significantly correlated with shear force. Negative correlation was established between drip loss and contributing factors (ISC, titin and nebulin). All results suggested that textural loss of post-mortem grass carp fillets was mainly mediated by the degradation of collagen and to a lesser extent by myofibrillar proteins at the early storage.
研究领域:
食品科学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ASIA-PACIFIC ENTOMOLOGY
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2017
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IF 1.046
Yunhua Zhang,Jinyun Ji,Xiao Zhao,Ruoheng Jin,Jianhong Li,Hu Wan
A previous study demonstrated that a β- N -acetyl- d -hexosaminidase ( NlHex4 ) from the brown planthopper could serve as a new potential target for biopesticides due to its requirement for molting, and lethal phenotypes were observed via RNA interference . However, the enzymatic properties of NlHex4 remain unclear. In the present study, NlHex4 was expressed, purified and characterized. Recombinant NlHex4 was functionally expressed in baculovirus-infected insect cells and purified with a molecular weight of approximately 70 kDa. Recombinant NlHex4 had an optimal pH and temperature of 6.0 and 60 °C, respectively. Moreover, recombinant NlHex4 exhibited thermal stability at 50 °C for at least 1 h. Furthermore, the activity of recombinant NlHex4 was inhibited by the metal ions Fe 2 + and Fe 3 + and the serine protease inhibitor phenylmethanesulfonyl fluoride. These results reveal the enzymatic properties of NlHex4 and provide a basis for future investigation of the interaction between HEX and chitin oligosaccharide .
研究领域:
昆虫学
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生物化学
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害虫管理
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产品关联
DOI
高影响因子
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2022
·Vol. 102
·期 13
·5858-5866
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IF 4.125
Jiandong Shen,Wei Zhang,Qixing Jiang,Pei Gao,Yanshun Xu,Wenshui Xia
BACKGROUND Textural deterioration is a serious problem in chilled fish flesh. Cysteine proteinases are proposed to participate in disintegration of collagen fibers during this process, while its mechanism remains elusive. In the present study, a cysteine proteinase was purified from grass carp muscle and identified by mass spectrometry, and its effect on structural changes of collagen fibers was investigated. RESULTS During storage at 4 °C, cysteine proteinase activity in fillets increased to 1.53-fold at day 5 and maintained a high level later, and this variable was related to a decline in shear force and an increase in drip loss. A 29 kDa cysteine proteinase was purified through ammonium sulfate precipitation and column chromatography, and identified as cathepsin L. Cathepsin L caused collagen fibers to partly disintegrate into fibril bundles and individual fibrils at 48 h, while the triple helical structure of collagen molecules remained stable. Release of soluble proteins and glycosaminoglycans from cathepsin L-treated collagen fibers was time dependent, coinciding with a release of 4.12 ± 0.13% and 8.57 ± 0.03% at 48 h respectively. However, 0.85 ± 0.02% of hydroxyproline was freed from cathepsin L-treated collagen fibers at 48 h. Furthermore, scanning electron microscopy revealed that the inhibitory effect of cathepsin L could retard the destruction of intramuscular connective tissues (IMCTs). CONCLUSION These results indicated that cathepsin L might be involved in collagen fiber breakdown by degrading collagen-associated proteoglycans during textural deterioration of grass carp. © 2022 Society of Chemical Industry.
研究领域:
食品科学
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生物化学
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水产养殖
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Limei Cai,Xiaoming Liu,Zhiqiang Tian,J.P. Michaud,Zhongjian Shen,Zhen Li,Songdou Zhang,Xiaoxia Liu
The widespread adoption of Bt crops expressing insecticidal proteins derived from Bacillus thuringiensis has created a need to assess the potential effects of these toxins on non-target organisms, especially species such as Arma custos , a generalist predator that provides important biological control services in many field crops in Asia. Direct dietary exposure of A. custos to Cry1Ah and Vip3Aa proteins produced no adverse effects on life history traits, despite continuous exposure throughout development and early adult life to concentrations significantly higher than the Bt protein concentration likely encountered by A.custos in the field, even when feeding directly on Bt plants. Enzyme-linked immunosorbent assay confirmed the presence of Bt proteins in A. custos midguts, but quantitative real-time PCR analysis of 12 genes associated with detoxification, antioxidative responses, immune responses, and metabolism revealed no significant changes in expression in adult bugs. Indirect exposure to these toxins via consumption of intoxicated prey, larvae of Helicoverpa armigera (Hübner), likewise produced no negative impacts on survival, development, adult weight, or female fecundity in either the F0 (exposed) or F1 (unexposed) generation, but female fresh weight was reduced in the F0 generation by the Cry1Ah (50 μg/g) treatment. Finally, a competitive binding assay with labelled protein and a ligand blotting assay both demonstrated that the Cry1Ah protein could not bind to receptors on the midgut brush border membrane vesicles (BBMVs) of A. custos adults. Therefore, we conclude that Cry1Ah and Vip3Aa proteins are unlikely to have significant negative effects on A. custos populations if employed as plant-incorporated protectants in field crops.
研究领域:
昆虫学
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环境科学
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农业科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）