JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
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2013
·Vol. 52
·期 3
·1724-1729
·
IF 1.123
Xu Xiaobian,Miao Yelian,Chen Jie Yu,Zhang Qimei,Wang Jining
S-allyl-L-cysteine (SAC) is a bioactive compound in garlic ( Allium sativum ). A novel process including soaking and homogeneous reaction was applied for the effective production of SAC with endogenous γ-glutamyltranspeptidase (γ-GTP, EC 2.3.2.2) in garlic. The effects of temperature and CaCl 2 concentration on γ-GTP activity in soaking, and the relationship of SAC production with γ-GTP activity in homogeneous reaction were investigated, using fresh garlic as raw material. The experimental results showed that the γ-GTP in fresh garlic was activated by soaking. The yield rate and the final content of SAC increased linearly with increasing initial γ-GTP activity in the homogeneous reaction at 37 °C. The final SAC content reached 606.3 μg/g (i.e. 32 times higher than that in fresh garlic) after soaking for 72 h in a 10-mM CaCl 2 solution at 10 °C, and the homogeneous reaction for 8 h at 37 °C. SAC was produced effectively through the homogeneous reaction with activated endogenous γ-GTP in garlic.
研究领域:
植物学
·
生物化学
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DOI
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JOURNAL OF PHYSICAL CHEMISTRY A
·
2020
·
IF 2.6
Tao Wang,Yangyang Liu,Yue Deng,Hanyun Cheng,Xiaozhong Fang,Liwu Zhang
The heterogeneous reaction of SO2 on manganese oxides is poorly understood. By means of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), this study investigated the reaction kinetics and product fractions on four types of manganese oxides. Due to the positive and negative moisture impacts, 68% RH (relative humidity) becomes the most favorable condition for the uptake of SO2. Mn3O4 shows the greatest uptake capacity of SO2, followed by MnO2 and Mn2O3, with that of MnO being the weakest. Curve-fitting procedures were undertaken to further dissect the product spectra. Increased RH facilitates the physical adsorption of SO2 and generally weakens the oxidation capacity of manganese oxides. The oxidation ability is greatest for MnO, followed by MnO2 and Mn3O4, with that of Mn2O3 being the weakest. Additionally, the particle acidity (pH) was estimated by the ionization equilibrium of sulfurous acid and the relative contributions of S(IV) species. MnO and Mn3O4 become more acidic as RH increases while Mn2O3 and MnO2 are the most acidic at 50% RH, which can be attributed to the different uptake capacities of SO2 and H2O on each sample. Overall, for the heterogeneous reaction of SO2 on manganese oxides, both particle type and moisture condition influence the reaction kinetics and product fractions. This work improves the understanding of the heterogeneous process on atmospheric manganese-rich particles.
研究领域:
环境化学
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大气科学
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表面化学
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气溶胶化学
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物理化学
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DOI
高影响因子
Biosensors-Basel
·
2021
·Vol. 11
·期 10
·362
·
IF 5.519
Ning Xia,Gang Liu,Xinyao Yi
The heterogeneous assays of proteases usually require the immobilization of peptide substrates on the solid surface for enzymatic hydrolysis reactions. However, immobilization of peptides on the solid surface may cause a steric hindrance to prevent the interaction between the substrate and the active center of protease, thus limiting the enzymatic cleavage of the peptide. In this work, we reported a heterogeneous surface plasmon resonance (SPR) method for protease detection by integration of homogeneous reaction. The sensitivity was enhanced by the signal amplification of streptavidin (SA)-conjugated immunoglobulin G (SA-IgG). Caspase-3 (Cas-3) was determined as the model. A peptide labeled with two biotin tags at the N- and C-terminals (bio-GDEVDGK-bio) was used as the substrate. In the absence of Cas-3, the substrate peptide was captured by neutravidin (NA)-covered SPR chip to facilitate the attachment of SA-IgG by the avidin-biotin interaction. However, once the peptide substrate was digested by Cas-3 in the aqueous phase, the products of bio-GDEVD and GK-bio would compete with the substrate to bond NA on the chip surface, thus limiting the attachment of SA-IgG. The method integrated the advantages of both heterogeneous and homogeneous assays and has been used to determine Cas-3 inhibitor and evaluate cell apoptosis with satisfactory results.Keywords:surface plasmon resonance;protease;caspase;avidin-biotin interaction
研究领域:
生物化学
·
分子生物学
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分析化学
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DOI
PubMed
高影响因子
TALANTA
·
2021
·
IF 6.057
Yaliang Huang,Ting Sun,Lin Liu,Ning Xia,Yuehua Zhao,Xinyao Yi
The hybridization and enzymolysis reactions for nucleic acid detection were carried out on the chip surface in the traditional surface plasmon resonance (SPR) biosensors. Herein, we proposed an innovative method for microRNA (miRNA) detection in which the hybridization-enzymolysis recycling reactions were performed in solution. Duplex-specific nuclease (DSN) and streptavidin-modified gold nanoparticles (SA-AuNPs) were employed for enhancing the assay sensitivity. In the absence of miRNA, the biotinylated DNA probe (bio-DNA-bio, biotin tags at both the 3′ and 5′ termini of DNA) was attached to the SA-modified chip through the SA-biotin binding, allowing the capture of SA-AuNPs with the same interaction. As a result, a larger SPR signal was attained. However, in the presence of miRNA, bio-DNA-bio hybridized with miRNA was digested by DSN. In this process, the miRNA strand remained intact and participated in the next hybridization-enzymolysis recycling process. Thus, one miRNA could promote the hydrolysis of many bio-DNA-bio probes and allow the generation of numerous bio-DNA fragments. Meanwhile, the produced bio-DNA competed with the undigested bio-DNA-bio to bind SA on the chip surface. The digestion of bio-DNA-bio and the competitive binding between bio-DNA-bio and bio-DNA led to the attachment of fewer SA-AuNPs and then smaller SPR signals. The change in SPR signal at the concentration as low as 1 fM miRNA has been readily determined. The strategy possessed the advantageous properties of simple operation, fast response, high sensitivity and excellent specificity, serving as a viable means for the fabrication of novel sensing platforms.
研究领域:
生物化学
·
分子生物学
·
分析化学
·
生物医学工程
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DOI
PubMed
高影响因子
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