EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2013
·Vol. 236
·期 5
·817-826
·
IF 1.436
Zhang Hongzhi,Li Wei,Rui Xin,Sun Xingmin,Dong Mingsheng
A novel food-grade strain Lactobacillus plantarum 70810 producing β-galactosidase with high transgalactosylation activity was isolated from Chinese paocai. The galactooligosaccharides (GOS) were synthesized by using this enzyme with a maximum yield of 44.3 % (w/w) from 400 g/L lactose at 45 °C for 10 h. The β-galactosidase from this strain was purified to homogeneity by ammonium sulfate precipitation, anion exchange chromatography and gel filtration chromatography. It was a heterodimer arrangement of approximately 105 kDa composed of two subunits of 35 and 72 kDa. The optimal pH of the purified β-galactosidase was 8.0 for both o -nitrophenyl-β- d -galactopyranoside ( o NPG) and lactose hydrolysis, and optimal temperature was 60 °C and 55 °C, respectively. Its K
m
and V
max values for o NPG and lactose were 0.89 ± 0.05 mM, 194 ± 3.0 μmoL/min/mg protein, and 9.88 ± 0.16 mM, 15.88 ± 0.21 μmoL/min/mg protein, respectively. This enzyme was slightly inhibited by the hydrolysis products, that is, glucose and galactose. Since the β-galactosidase from L. plantarum 70810 exhibited higher transgalactosylation activity, strong affinity for lactose and low end-product inhibition, it was suggested to be a potential candidate for the synthesis of prebiotic GOS.
研究领域:
食品科学
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微生物学
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高影响因子
Food & Function
·
2015
·Vol. 6
·期 10
·3291-3295
·
IF 2.791
Hui-da Wan,Yong-mei Xia
Enzymatic hydrolysis and transgalactosylation of stevioside (St) were investigated using a β-galactosidase from Sulfolobus sp. The hydrolysis yielded steviol as the main final product. Under the optimal transgalactosylation conditions, the highest conversion of stevioside was 87.3% with lactose as a donor, several galactosylated products (St-Gals) were obtained. Metal ions such as Na+, K2+, Ca2+, Ba2+, Mn2+ and Mg2+ (2 mM) did not affect the transgalactosylation activity, while Fe2+, Fe3+ and Cu2+ reduced the transgalactosylation activity of β-galactosidase to 64%, 33% and 18%, respectively.
研究领域:
生物化学
·
食品科学
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DOI
高影响因子
FOOD CHEMISTRY
·
2013
·
IF 3.334
Wei Wei,Danping Qi,Hai-zhen Zhao,Zhao-xin Lu,Fengxia Lv,Xiaomei Bie
A study of an enzymatic method for the production of galactosylglycerol is described. The effects of enzyme sources, enzyme amount, reaction temperature, reaction time, substrate ratio of glycerol to galactose, buffer content and pH on galactosylglycerol yield (mg/ml) were investigated. Under the optimum reaction conditions of β-galactosidases from Kluyveromyces lactis 240 U/ml, temperature 40 °C, time 24 h, buffer amount 60% (percent volume of buffer to that of substrates, pH 6.5), and the substrate molar ratio of 10 (glycerol16 mmol:galactose 1.6 mmol), the yield of galactosylglycerol was up to 116.47 mg/ml (galactose conversion 55.88%). The product was purified by activated charcoal and Sephadex G-15 column chromatography, up to 96%. The purified galactosylglycerol was fully characterised by MS and NMR, and identified as a mixture of (2R)- and (2S)- 3-O-β-D-galactopyranosyl-glycerol.
研究领域:
生物化学
·
酶工程
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DOI
PubMed
高影响因子
ELECTROANALYSIS
·
2015
·Vol. 28
·期 1
·183-188
·
IF 2.138
Jia Xie,Chao Chen,Yuanqing Zhou,Junjie Fei,Yonglan Ding,Jia Zhao
A novel amperometric biosensor was developed by immobilizing galactose oxidase (GAox) on poly (L-lactide) stabilized gold nanoparticles (Au@PLLA) modified graphene nano-composite film (RGO-Au@PLLA/GAox). The direct electron transfer (DET) of GAox was achieved. Cyclic voltammetry of the GAox in the RGO-Au@PLLA film revealed a pair of well-defined and quasireversible peaks at about −0.137 V (vs. SCE), which is characterized of the Cu(II)/Cu(I) redox couple for the galactose oxidase. Amperometric response was measured as a function for the determination of galactose (GA) and dihydroxyacetone (DHA). The constructed biosensor also possesses good stability, reproducibility and anti-interference ability.
研究领域:
生物传感器技术
·
电化学分析
·
材料科学
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高影响因子
BIOCATALYSIS AND BIOTRANSFORMATION
·
2016
·
IF 0.892
Wei Wei,Danping Qi,Mingming Diao,Lu Zhaoxin,Fengxia Lv,Haizhen Zhao
In this study, the synthesis of 3-O-β-D-galactopyranosyl-sn-glycerol (GG) was performed by the reverse hydrolysis of D-galactose and glycerol using β-galactosidase from Kluyveromyces lactis. Four process variables, reaction temperature (30.0–45.0 °C), reaction time (24–48 h), enzyme concentration (150.00–350.00 U/mL), and substrate molar ratio (glycerol:D-galactose, 7.5:12.5 mmol/mmol) were investigated and optimized via response surface methodology (RSM) for optimal GG synthesis. Both quadratic equations and the optimal reaction conditions were established. Results showed that the four variables, i.e., reaction temperature, reaction time, enzyme concentration, and substrate molar ratio had significant (p < 0.0001) effects on the synthesis of GG. The optimal reaction conditions were identified as 350.00 U/mL of β-galactosidase concentration and 8.65:1.00 of substrate molar concentration ratio (glycerol: D-galactose) at 39.8 °C and 48 h of reaction. Under these conditions, the GG concentration was 140.03 g/L and GG yield was 55.71%, which both were close to the predicted values (143.26 g/L and 56.73%). This finding proves the RSM to be a useful tool in optimizing process conditions for GG synthesis.
研究领域:
生物化学
·
食品科学
·
酶工程
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高影响因子
MOLECULES
·
2019
·Vol. 24
·期 15
·2769
·
IF 3.06
Xican Li,Xiaojian Ouyang,Minshi Liang,Dongfeng Chen
The biological process, 3-O-galactosylation, is important in plant cells. To understand the mechanism of the reduction of flavonol antioxidative activity by 3-O-galactosylation, myricetin-3-O-galactoside (M3OGa) and myricetin aglycone were each incubated with 2 mol α,α-diphenyl-β-picrylhydrazyl radical (DPPH•) and subsequently comparatively analyzed for radical adduct formation (RAF) products using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS) technology. The analyses revealed that M3OGa afforded an M3OGa–DPPH adduct (m/z873.1573) and an M3OGa–M3OGa dimer (m/z958.1620). Similarly, myricetin yielded a myricetin–DPPH adduct (m/z711.1039) and a myricetin–myricetin dimer (m/z634.0544). Subsequently, M3OGa and myricetin were compared using three redox-dependent antioxidant analyses, including DPPH•-trapping analysis, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-trapping analysis, and•O2inhibition analysis. In the three analyses, M3OGa always possessed higher IC50values than those of myricetin. Conclusively, M3OGa and its myricetin aglycone could trap the free radical via a chain reaction comprising of a propagation step and a termination step. At the propagation step, both M3OGa and myricetin could trap radicals through redox-dependent antioxidant pathways. The 3-O-galactosylation process, however, could limit these pathways; thus, M3OGa is an inferior antioxidant compared to its myricetin aglycone. Nevertheless, 3-O-galactosylation has a negligible effect on the termination step. This 3-O-galactosylation effect has provided novel evidence that the difference in the antioxidative activities of phytophenols exists at the propagation step rather than the termination step.
研究领域:
植物化学
·
生物化学
·
分析化学
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高影响因子
PeerJ
·
2025
·
IF 2.4
Shu-Dong Zhang,Ling-Ling Chen,Chao-Yue Li,Xiao-Qing Long,Xue Yang,Xiao-Duo He,Li-Wen Du,Heng-Feng Yang,Li-Zhen Ling
Diaporthe Z1-1N, the primary causal agent of soft rot disease in kiwifruit, exhibited higher pectinase activity compared to cellulase activity in both in vitro and in vivo incubation models. To gain deeper insights into the role of pectinases in the pathogenicity of this fungus, we evaluated the effects of incubation temperature (ranging from 18 to 38 °C), duration (1 to 7 days), and medium pH (4.0 to 9.0) on the activities of two crucial pectinases: polygalacturonase (PG) and polymethylgalacturonase (PMG). Our single-factor experiments revealed that the optimal conditions for maximizing PMG yield were a pH of 7.5 and a temperature of 28 °C, with peak activity occurring after three days of incubation. Notably, PG activity peaked on the fourth day under the same pH and temperature conditions. Under the optimal conditions identified through an orthogonal experimental design, PMG exhibited higher activity than PG. Further analysis showed that temperature was the most influential factor on PMG activity, followed by incubation duration and pH. The lesion size caused by the purified pectinase extracts was 50% the lesion size that caused by the fungal mycelium of Diaporthe Z1-1N. These findings underscore the significance of PG and PMG as key virulence factors in the pathogenicity of Diaporthe Z1-1N, providing a solid scientific basis for future research into the functions of these enzymes.
研究领域:
植物病理学
·
酶学
·
微生物学
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DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Qiqi Xing,Xiaoyu Wang,Qi Li,Changning Lu,Yi Wu,Jianjun Pei,Linguo Zhao
β-Galactosidase is a crucial class of biocatalysts, renowned for its ability to catalyze the hydrolysis of non-reducing terminal β-d-galactoside bonds, while also demonstrating significant potential in galactosylation synthesis reactions. In this study, a novel GH1 β-galactosidase gene VthBga was screened and cloned from Vulcanisaeta thermophila . Soluble expression of the VthBga was induced at 47 °C in Escherichia coli BL21. VthBga exhibited optimal activity at 95 °C and pH 4.5 with p -nitrophenyl-β-d-galactoside ( p NPGal) as a substrate and displayed excellent thermotolerance below 90 °C. In addition, VthBga possessed not only a diverse array of substrate hydrolytic activities but also inherent galactosylation activity, rendering it a promising candidate for the galactosylation of the natural compound. To enhance its transglycosylation activity, a superior mutant Vth-A266G/F441T was obtained by adjusting the transglycosylation/hydrolysis ratio through a semi-rational design. Under optimal conditions, this mutant produced 44.5 % tyrosol galactoside, representing a significant 2.3-fold increase compared to the wild-type strain, highlighting its practical value in related biosynthesis applications.
研究领域:
生物化学
·
分子生物学
·
酶工程
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Jia-Ying Zhao,Tao Hong,Yan-Jie Hou,Xiao-Xiao Song,Jun-Yi Yin,Fang Geng,Shao-Ping Nie
The structural characteristics of two water-extracted pectic polysaccharides from Fructus aurantii were investigated, and the impacts of their structures on the emulsifying stability were evaluated. FWP-60 (extracted by cold water and followed 60 % ethanol precipitation) and FHWP-50 (extracted by hot water and followed 50 % ethanol precipitation) were both high methyl-esterified pectins, which were composed of homogalacturonan (HG) and highly branched rhamnogalacturonan I (RG-I) regions. The weight-average molecular weight, methyl-esterification degree (DM) and HG/RG-I ratio of FWP-60 were 1200 kDa, 66.39 % and 4.45, respectively, which were 781 kDa, 79.10 % and 1.95 for FHWP-50. The methylation and NMR analysis of FWP-60 and FHWP-50 demonstrated that the main backbone consisted of different molar ratios of →4)-α-Gal p A-(1 → and →4)-α-Gal p A-6- O -methyl-(1 →, and the side chains contained arabinan and galactan . Moreover, the emulsifying properties of FWP-60 and FHWP-50 were discussed. Compared with FHWP-50, FWP-60 had better emulsion stability. Overall, pectin had a linear HG domain and a small number of RG-I domain with short side chains to facilitate the stabilization of emulsions in Fructus aurantii. A comprehensive knowledge of the structure characteristic and emulsifying property would enable us to provide more information and theoretical guidance for the structure and emulsion preparation of Fructus aurantii pectic polysaccharides.
研究领域:
食品科学
·
化学
·
生物材料
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PubMed
高影响因子
JOURNAL OF FOOD BIOCHEMISTRY
·
2020
·Vol. 44
·期 3
·e13133
·
IF 1.662
Haidong Tan,Guojun Yang,Wei Chen,Qishun Liu,Kuikui Li,Heng Yin
Endo-polygalacturonase II B (PgaB) from Aspergillus luchuensis was orthologous to endo-polygalacturonase from Aspergillus niger with mutant sites Thr42Ser and Glu52Ala. Mature pga B gene was cloned from the genomic DNA of A. luchuensis and secreted expressed with over 90% purity in Pichia Pastoris and reached 1.0 g/L after 144 hr culture. The recombinant PgaB was further purified by Ni-NTA chromatography. Using polygalacturonic acid (PGA) as substrate, the optimal condition for PgaB activity was 40°C and pH 4.5, respectively. Km and Vmax of PgaB were 0.19 mmol/l and 103.58 μmol min −1 mg −1 , respectively. The relative activity of PgaB remained more than 60% and 40% of maximum activity at 50 and 60°C for 7 hr. PgaB increased the light transmittance by 85% and showed high efficiency in juice clarification. The main product was galacturonic acid oligosaccharides with degrees of polymers (DP) 1–3. The PgaB is a potential pectinolytic enzyme in food industries. Practical applications Endo-polygalacturonase II B (PgaB) was identified from Aspergillus luchuensis , a filamentous fungus widely used in food and beverage fermentation in East Asia. PgaB still kept its most activity at 60°C for 7 hr. Polygalacturonic acid (PGA) can be digested effectively by the PgaB and the main products are galacturonic acid oligosaccharides with degrees of polymers (DP) 1–3. PgaB shows high efficiency in juice clarification. The PgaB is a potential pectinolytic enzyme for the applications in food industries.
研究领域:
酶学
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食品科学
·
微生物学
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PubMed
高影响因子
PLANT PHYSIOLOGY AND BIOCHEMISTRY
·
2021
·
IF 4.27
Xuqiu He,Ronghao Huang,Lipeng Liu,Yingying Li,Wenzhao Wang,Qingshan Xu,Youben Yu,Tianshan Zhou
Anthocyanins are a group of natural water-soluble pigments in plants that contribute to the pink-purple color of a range of tissues. Because anthocyanins have various biological activities in human health, there is great research interest in the development of anthocyanin-rich foods and beverages, including purple shoot tea. Anthocyanidin 3- O -galactosides have been identified as one of the main anthocyanin components in purple shoot tea, but the enzyme responsible for their biosynthesis remains unclear. UDP-galactose anthocyanidin 3- O -galactosyltransferase (UA3GalT) is presumed to catalyze the galactosylation of anthocyanidin. Therefore, we assayed the UA3GalT activity in five tea samples with varying degrees of purple color and found that its activity was strongly positively correlated (r = 0.929, p < 0.05) with anthocyanin content. Phylogenetic analysis and sequence alignment suggested that CsUGT78A15 encoded a UA3GalT enzyme. Enzymatic assays indicated that r Cs UGT78A15 could catalyze the synthesis of cyanidin 3- O -galactoside and delphinidin 3- O -galactoside using UDP-galactose as a sugar donor, and it showed higher catalytic efficiency towards delphinidin than cyanidin. These results indicate that Cs UGT78A15 acts as a UA3GalT in vitro . Subcellular localization showed that Cs UGT78A15 was located in the endoplasmic reticulum (ER) and nucleus, consistent with the location of anthocyanin synthesis. Transient overexpression of CsUGT78A15 in the fruit of mature ‘Granny Smith’ apples showed that the upregulation of CsUGT78A15 promoted cyanidin 3- O -galactoside accumulation in apple skins. These results suggested that Cs UGT78A15 could catalyze galactosylation of anthocyanidins in planta . Our findings provide insight into the biosynthesis of anthocyanins in tea plants .
研究领域:
植物学
·
植物生物化学
·
分子生物学
·
遗传学
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PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 69
·64841-64846
·
IF 3.289
Youzhi Zhou,Jianlin Chu,Jinsong Zhang,Ke Liu,Bingfang He
Efficient synthesis of unitary β-galactosyl nucleoside analogues was successfully achieved in a 10% DMSO solvent system, catalyzed by a newly isolated solvent-stable β-galactosidase from solvent-tolerant Bacillus megaterium YZ08. The most efficient sugar donor for the galactosylation of nucleoside analogues was lactose rather than nitrophenyl glycoside. However, it was accompanied with the formation of complicated digalactosyl nucleoside analogues in the buffer system. The addition of DMSO not only prominently increased the stabilization of β-galactosidase but also regulated the products from complicated products to unitary monogalactosyl nucleoside analogues, which could significantly simplify the process of subsequent separation. Strikingly, the affinity of β-galactosidase to 3′-azido-3′-deoxythymidine in 10% DMSO was significantly enhanced, and the catalytic efficiency (kcat/Km) was doubled as compared to that in buffer solution. These results indicated that solvent-stable glycosidase possesses attractive potency in biosynthesis as well as in regulation of the glycoside prodrugs by adjusting the reaction solvent system.
研究领域:
生物化学
·
药学
·
酶学
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DOI
高影响因子
危险品化学品经营许可证（带存储）