FOOD HYDROCOLLOIDS
·
2021
·
IF 9.147
Xiuying Han,Huiliang Wen,Yu Luo,Jun Yang,Wenhao Xiao,Xiaoyao Ji,Jianhua Xie
To overcome the limited surface area of starch and improve the adsorption capacity of starch, porous starch has been widely produced in various fields. In this study, the different enzyme activities of α-amylase (AM), glucoamylase (GAM), and mixed enzyme (ME) were used to prepare different types of porous maize starch, and the microstructure, particle morphology, adsorption, and gelatinization characteristics of the porous starch were studied. Scanning electron microscopy showed porous structures with diverse pore size distribution and pore area depending on the enzyme type and its activities; AM produced the largest holes, GAM produced the deepest holes, and ME produced large and deep holes. Adsorptive capacity was significantly affected by enzymatic modification being greater influenced by GAM. The porous starches had higher relative crystallinity as deduced from X-ray diffraction and Fourier transform infrared spectroscopy . The MA-treated starch had higher solubility whereas swelling capacity, peak viscosity, final viscosity, breakdown, and setback of both treatments were decreased compared to the native starch. The results indicate porous maize starch can provide different functions according to the action pattern of enzymes. The type of enzyme and its enzyme activity can be used to produce the ideal cavity and pore size starch granules , which expands its application scope.
研究领域:
食品科学
·
生物化学
✓ 已验证
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Yingxin Wu,Kainan Hong,Juzhen Yi,Juncheng Shen,Liqun Yang
Surface-enhanced Raman spectroscopy (SERS) shows unique advantages for the study of protein structure in water environment, because it can provide plenty of structural information of proteins in addition to very weak Raman scattering signal of water. To achieve the Raman-enhanced effect of proteins, the challenge is to prompt protein molecules to approach the surface of noble metal (such as Ag and Au). Based on the enzyme–substrate specificity, the Ag nanoparticles-encapsulated amylopectin (Amyp/AgNPs) colloid was prepared as an aqueous SERS substrate to obtain the Raman-enhanced effect of amylase. Dynamic light scattering analysis showed that the hydrodynamic diameter of the Amyp/AgNPs colloid was in the range of 40–700 nm. UV–vis spectroscopy and energy dispersive spectroscopy confirmed the formation of Ag nanoparticles in the Amyp/AgNPs colloid. The Ag nanoparticles in the Amyp/AgNPs colloid were observed as globular homogeneous particles in the sizes ranging from 10 to 20 nm using transmission electron microscopy (TEM). The crystalline Ag nanoparticles were further observed in the high-resolution TEM image. The obviously enhanced Raman bands assigned to the amino acid residues and the secondary structures of α -amylase and β -amylase appeared in their SERS spectra, which were further analyzed following the principal component analysis (PCA) process. The Raman-enhanced mechanism is considered as that the specificity of two amylases with amylopectin in the Amyp/AgNPs colloid may prompt them to approach the surface of Ag nanoparticles and then produce the significant SERS effect. The SERS strategy based on enzyme–substrate specificity is thus anticipated to apply for structural analysis of enzyme.
研究领域:
生物化学
·
分析化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2023
·
IF 8.1
Kai Zhang,Xiaojing Tian,Ruixi Shen,Yang Wang,Yafei Zhang,Wenhang Wang
We investigated the inhibition effect of carboxymethylated cellulose nanofibrils with four different surface chargeon α-amylase and amyloglucosidase via enzyme activity inhibition assay, fluorescence spectra and secondary structure change analysis. These results revealed that cellulose nanofibril with lowest surface charge displayed the greatest inhibition effects against α-amylase (9.81 mg/mL) and amyloglucosidase (13.16 mg/mL). All cellulose nanofibrils in starch model significantly ( p < 0.05) inhibited the starch digestion, where the inhibition effect was negatively correlated with the magnitude of particle surface charge. Cellulose nanofibrils could bind α-amylase or amyloglucosidase to form new complex in the manner of static quenching. The thermodynamic parameters demonstrated that the cellulose nanofibrils-starch hydrolase (α-amylase or amyloglucosidase) complexes were formed spontaneously via hydrophobic effects. Additionally, Fourier transform Infrared spectra exhibited the changes in the fraction of secondary structures of starch hydrolase after the interactions with carboxymethylated cellulose nanofibrils. These data provide a convenient and simple method tailor gastrointestinal digestion of starch by changing cellulose surface charge, to control postprandial serum glucose upsurge.
研究领域:
生物化学
·
食品科学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Xiong Lin,Siwei Sun,Bailong Wang,Baodong Zheng,Zebin Guo
Lotus seed starch (LS) was enzymatically hydrolyzed by pullulanase, β-amylase and α-amylase to obtain three types of starch nanoparticles (SNPs): P-SNPs, β-SNPs and α-SNPs, respectively. The structure and physicochemical properties of lotus seed starch nanoparticles (LS-SNPs) were systematically studied by Laser particle size analysis, Scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectrometry, Nuclear magnetic resonance (NMR) and Gel permeation chromatography (GPC). The results showed that compared to LS (10,466.7 ± 230.9 nm), the D [3,2] of P-SNPs were (334.7 ± 16.2), which indicated that LS was decomposed into LS-SNPs with low degree of polymerization. P-SNPs showed the highest efficiency, with 81.74% of samples reaching the nanoscale. The particle size order was LS > β-SNPs (α-SNPs) > P-SNPs. XRD results showed P-SNPs had the highest crystallinity 65.07%. During preparation of LS-SNPs, crystal region was destroyed, and double helix structure became stronger, but no new functional groups were introduced. P-SNPs had the smallest amorphous area and also showed a minimal molecular weight and the broadest molecular weight distribution. P-SNPs had the smallest particle size and the highest crystallinity, so P-SNPs were the best of all LS-SNPs.
研究领域:
食品科学
·
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biotechnology for Biofuels
·
2019
·Vol. 12
·期 1
·1-15
·
IF 5.452
Fang Wei,Xue Saisai,Deng Pengjun,Zhang Xuecheng,Wang Xiaotang,Xiao Yazhong,Fang Zemin
Background Starch is an inexpensive and renewable raw material for numerous industrial applications. However, most starch-based products are not cost-efficient due to high-energy input needed in traditional enzymatic starch conversion processes. Therefore, α-amylase with high efficiency to directly hydrolyze high concentration raw starches at a relatively lower temperature will have a profound impact on the efficient application of starch. Results A novel raw starch digesting α-amylase (named AmyZ1) was screened and cloned from a deep-sea bacterium Pontibacillus sp. ZY. Phylogenetic analysis showed that AmyZ1 was a member of subfamily 5 of glycoside hydrolase family 13. When expressed in Escherichia coli , the recombinant AmyZ1 showed high activity at pH 6.0–7.5 and 25–50 °C. Its optimal pH and temperature were 7.0 and 35 °C, respectively. Similar to most α-amylases, AmyZ1 activity was enhanced (2.4-fold) by 1.0 mM Ca 2+ . Its half-life time at 35 °C was also extended from about 10 min to 100 min. In comparison, AmyZ1 showed a broad substrate specificity toward raw starches, including those derived from rice, corn, and wheat. The specific activity of AmyZ1 towards raw rice starch was 12,621 ± 196 U/mg, much higher than other reported raw starch hydrolases. When used in raw starch hydrolyzing process, AmyZ1 hydrolyzed 52%, 47% and 38% of 30% (w/v) rice, corn, and wheat starch after 4 h incubation. It can also hydrolyze marine raw starch derived from Chlorella pyrenoidosa , resulting in 50.9 mg/g DW (dry weight of the biomass) of reducing sugars after 4 h incubation at 35 °C. Furthermore, when hydrolyzing raw corn starch using the combination of AmyZ1 and commercial glucoamylase, the hydrolysis rate reached 75% after 4.5 h reaction, notably higher than that obtained in existing starch-processing industries. Conclusions As a novel raw starch-digesting α-amylase with high specific activity, AmyZ1 efficiently hydrolyzed raw starches derived from both terrestrial and marine environments at near ambient temperature, suggesting its application potential in starch-based industrial processes.
研究领域:
生物化学
·
工业微生物学
·
酶工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2015
·Vol. 81
·期 6
·
IF 3.668
Zhoukun Li,Jiale Wu,Biying Zhang,Fei Wang,Xianfeng Ye,Yan Huang,Qiang Huang,Zhongli Cui
A novel α-amylase, AmyM, was purified from the culture supernatant of Corallococcus sp. strain EGB. AmyM is a maltohexaose-forming exoamylase with an apparent molecular mass of 43 kDa. Based on the results of matrix-assisted laser desorption ionization–time of flight mass spectrometry and peptide mass fingerprinting of AmyM and by comparison to the genome sequence of Corallococcus coralloides DSM 2259, the AmyM gene was identified and cloned into Escherichia coli. amyM encodes a secretory amylase with a predicted signal peptide of 23 amino acid residues, which showed no significant identity with known and functionally verified amylases. amyM was expressed in E. coli BL21(DE3) cells with a hexahistidine tag. The signal peptide efficiently induced the secretion of mature AmyM in E. coli. Recombinant AmyM (rAmyM) was purified by Ni-nitrilotriacetic acid (NTA) affinity chromatography, with a specific activity of up to 14,000 U/mg. rAmyM was optimally active at 50°C in Tris-HCl buffer (50 mM; pH 7.0) and stable at temperatures of <50°C. rAmyM was stable over a wide range of pH values (from pH 5.0 to 10.0) and highly tolerant to high concentrations of salts, detergents, and various organic solvents. Its activity toward starch was independent of calcium ions. The Km and V max of recombinant AmyM for soluble starch were 6.61 mg ml−1 and 44,301.5 μmol min−1 mg−1, respectively. End product analysis showed that maltohexaose accounted for 59.4% of the maltooligosaccharides produced. These characteristics indicate that AmyM has great potential in industrial applications.
研究领域:
生物化学
·
酶学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2024
·
IF 6
Yanan Wang,Xuezhi Tian,Zehua Zhang,Meiling Tian,Fusheng Zhang
The aim of this study is to enhance the efficiency of enzymes, reduce operational costs, and increase production output. Experimental research shows that ultrasound positively impacted the activity of α-amylase and glucoamylase, with the peak α-amylase activity observed at 30 W for 5 min and the highest glucoamylase activity at 60 W for 3 min. Ultrasonication extended the optimal temperature of both enzymes, but had no effect on the optimal pH. According to the kinetic experiments, ultrasonic treatment could improve the catalytic efficiency of α-amylase and glucoamylase. Furthermore, the SDS-PAGE results revealed that ultrasound treatment did not alter the molecular weights of the enzymes and their primary structures; The circular dichroism and fluorescence spectroscopy analysis indicated the secondary structural components, especially the α-sheet and the tryptophan fluorescence intensity, were notably affected by ultrasound. The changes in the secondary and tertiary structure of α-amylase and glucoamylase suggest that ultrasonic treatment may enhance their activities. Our findings provide a theoretical basis for the efficient utilization of α-amylase and glucoamylase through understanding the enzyme structure changes after ultrasound.
研究领域:
生物化学
·
酶学
·
超声技术
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yajuan Qin,Xiaoai Chen,Fei Xu,Kexue Zhu,Ping Wang,Yutong Zhang,Yanjun Zhang
The human dietary system, which contains a variety of compounds such as polyphenols and polysaccharides, is very complex. Whether polysaccharides affect the inhibitory of polyphenol mixtures on α-amylase needs to be further investigated. The aim of this study was to analyze the effect and mechanism of pectin on the inhibition of α-amylase by a mixture of rutin and quercetin (R–Q). Results revealed that the inhibition and quenching affinity of R–Q for α-amylase was enhanced by pectin. The Stern-Volmer quenching constant of R–Q–α-amylase was increased by pectin from (6.08 ± 0.453) × 10 3 mL/mg to (9.80 ± 0.285) × 10 3 mL/mg. Pectin enhanced the ability of R–Q to inhibit α-amylase for two main reasons. On the one hand, it was owing to the binding of pectin to rutin, which increased the opportunity for quercetin to bind to the active center of α-amylase, thus enhancing the inhibitory effect of R–Q on α-amylase. On the other hand, pectin and quercetin simultaneously bound to different sites of α-amylase by noncovalent interactions to form the ternary complex of pectin–α-amylase–quercetin. The conformation of α-amylase and the hydrophobicity of amino acid residues were altered by the ternary complex, thereby enhancing the hydrogen bonding in the reaction system.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Chemistry-X
·
2024
·
IF 6.5
Maiquan Li,Yunxia Dong,Mangjun Kang,Tiantian Tao,Wenlan Li,Sheng Zhang,Wei Quan,Zhonghua Liu
Hyperglycemia can cause early damage to human bady and develop into diabates that will severely threaten human healthy. The effectively clinical treatment of hyperglycemiais is by inhibiting the activity of α-amylase. Black tea has been reported to show inhibitory effect on α-amylase and can be used for hyperglycemia treatment. However, the mechanism underlying is unclear. In this study, in vivo experiment showed that black tea theaflavins extract (BTE) effectively alleviated hyperglycemia. In vitro experiment showed that the effects may be caused by the interation between theaflavins and α-amylase. While TF1 and TF3 were mixed type inhibitors of α-amylase, TF2A and TF2B were competitive inhibitors of α-amylase. Molecular docking analysis showed that theaflavins monomers interacted with the hydrophobic region of α-amylase. Further study verified that monomer-α-amylase complex was spontaneously formed depending on hydrophobic interactions. Taken together, theaflavins showed potential anti-hyperglycemia effect via inhibiting α-amylase activity. Our results suggested that theaflavins might be utilized as a new type of α-amylase inhibitor to prevent and cure hyperglycemia.
研究领域:
营养学
·
药理学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUNGAL GENETICS AND BIOLOGY
·
2013
·
IF 3.263
Yibo Hu,Guodong Liu,Zhonghai Li,Yuqi Qin,Yinbo Qu,Xin Song
Heterotrimeric G proteins (G proteins) have been extensively investigated for their regulatory functions in morphogenesis and development in filamentous fungi. In addition, G proteins were also shown to be involved in the regulation of cellulase expression in some fungi. Here, we report the different regulatory effects of PGA3, a group III G protein α subunit, on the expressions of amylases and cellulases in Penicillium decumbens . Deletion of pga3 resulted in impaired amylase production and significantly decreased transcription of the major amylase gene amy15A . Supplementation of exogenous cAMP or its analog dibutyryl-cAMP restored amylase production in Δ pga3 strain, suggesting an essential role of PGA3 in amylase synthesis via controlling cAMP level. On the other hand, the transcription of major cellulase gene cel7A-2 increased, nevertheless cellulase activity in the medium was not affected, in Δ pga3 . The above regulatory effects of PGA3 are carbon source-independent, and are achieved, at least, by cAMP-mediated regulation of the expression level of transcription factor AmyR. The functions of PGA3 revealed by gene deletion were partially supported by the analysis of the mutant carrying dominantly-activated PGA3. The results provided new insights into the understanding of the physiological functions of G protein-cAMP pathway in filamentous fungi.
研究领域:
分子生物学
·
微生物学
·
真菌遗传学
✓ 已验证
DOI
PubMed
高影响因子
Food Bioscience
·
2021
·
IF 4.24
Hangyan Ji,Xiaoxiao Li,Tong Jiang,Qi Fang,Yuxiang Bai,Jie Long,Long Chen,Zhengyu Jin
By heterologous expression of a gene from Palaeococcus ferrophilus , a novel recombinant enzyme designated AMPf was obtained and proved to be an amylolytic enzyme with unique catalytic characteristics. The optimal temperature and pH of AMPf were 50 °C and 7.0 respectively. Although sequence analysis and acarbose hydrolysis ability indicated that AMPf belongs to the subfamily GH13_20, interestingly, this enzyme hardly acts on cyclodextrins and pullulan distinguishing it from most enzymes in this subfamily. AMPf hydrolyzes starches to glucose, maltose , maltotriose , and maltotetrose as main products. AMPf mainly liberates glucose from starch with the concentration of 1% (w/v), while it shows malto-oligosaccharide forming ability with higher starch concentration of 4% (w/v). Also, the 4,6-ethylidene-4-nitrophenyl-maltoheptaose hydrolysis ability further indicates the unique combination endo-acting and glucose releasing exo-acting activtity of AMPf. AMPf could utilize maltose and maltotriose to produce malto-oligosaccharides by transglycosylation activity. It was proven AMPf has application protential in malto-oligosaccharides production.
研究领域:
生物化学
·
酶工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Jing Meng,Qingyue Li,Zengyuan Cao,Dongyu Gu,Yunxiao Wang,Yunci Zhang,Yi Wang,Yi Yang,Fei He
In the present study, an efficient method based on ligand fishing and high-speed counter-current chromatography (HSCCC) was established to screen, enrich and separate the active components with the α-amylase inhibitory activity from a traditional dish Toona sinensis . The active components were screened from T. sinensis by ligand fishing using the magnetic immobilized α-amylase prepared through solvothermal and crosslinking methods. HSCCC was used to separate the target compound according to the K value. As a result, a potential active compound 1,2,3,4,6-penta-O-galloyl-β- d -glucose and a non-target compound quercetin-3-O-α-L-rhamnopyranoside were separated and identified. In - vitro experiments indicated that 1,2,3,4,6-penta-O-galloyl-β- d -glucose had the activity against α-amylase and the IC 50 value was 93.49 ± 0.80 μg/mL which was higher than that of the non-target compound. The result further confirmed the molecular fishing effect of magnetic immobilized α-amylase. The present study can not only find and separate the hypoglycemic substances in T. sinensis quickly and effectively, but also can provide a new approach for the study of natural active components.
研究领域:
植物化学
·
药理学
✓ 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）