INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2022
·Vol. 57
·期 4
·2556-2567
·
IF 3.612
Xiuyun Guo,Junjun Wu,Xiangren Meng,Yawei Zhang,Zengqi Peng
Summary This study investigated the effects of l -lysine (Lys) and l -histidine (His) on the oxidative characteristics and gel properties of porcine myofibrillar proteins (MP). Results showed that Lys and His had a strong ferrous ion-chelating ability and hydroxyl radical-scavenging activity. Moreover, Lys and His inhibited the protein carbonyl formation and MP aggregation at 0.2 M and 0.6 M NaCl, respectively, in a dose-dependent manner. Furthermore, 2 and 4 mg mL −1 Lys and His decreased the oxidation-induced loss of the tertiary structure of MP accompanied by the lower surface hydrophobicity. The water-holding capacity and gel strength of MP gels increased with increasing Lys and His concentrations due to more regular and lamellar structures with smaller and homogeneous pores at 0.6 M NaCl and more orderly crosslinking via fibrous filament at 0.2 M NaCl. In summary, Lys and His chelated the ferrous ions and scavenged hydroxyl radicals, decreased the oxidation-induced physicochemical changes, thus preventing oxidative damage during the formation of a three-dimensional gel network, which resulted in better gel quality.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2024
·Vol. 26
·期 7
·943-950
·
IF 2.6
Jinqiu Fu,Mengyang Cai,Yuzhong Shi,Yihang Hou,Rongxi Guo,Chiyi Wang,Jingjing Zhao,Wei Zhuang,Hanjie Ying,Pengpeng Yang,Keke Zhang
L-Alanyl-L-glutamine (Ala–Gln) is a dipeptide which is widely used in medical and nutritional fields. Two new crystalline forms (form III and form IV) and a DMSO solvate form (SDMSO) of Ala–Gln were discovered in this study, which were distinguished from the known forms by Raman spectroscopy and powder X-ray diffraction (PXRD). Single crystal structures of the three new solid forms were obtained. Moreover, the crystal structure data of known forms: form II, dihydrate form (2H) and ethanol solvate form (SEtOH), which have not been reported to the best of our knowledge, were solved. The results showed that there were four kinds of molecular arrangements and frameworks in the Ala–Gln solid forms. The comparison of the molecular arrangements and cell parameters indicated that the forms III, 2H and SEtOH were isomorphic. The hydrogen bonding network of the DMSO solvate was different from those of forms II, III and IV. By comparing the bulk density, lattice energy and thermal analysis results of the three polymorphs of Ala–Gln, the order of bulk density and lattice energy was consistent with the decomposition enthalpy. Besides that, it was found that the crystal shape of the solvates can be retained after solvent removal.
研究领域:
药学
·
晶体学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2018
·
IF 5.089
Xiaoxu Zhu,Linxian Li,Shiyi Li,Cheng Ning,Cunliu Zhou
The effects of l –arginine (Arg) and l –lysine (Lys) on the emulsifying properties of the salt-soluble meat proteins (SSMPs)–soybean oil emulsion (SSOE) and soybean oil–water emulsion (SWE) were evaluated to ascertain their roles in improving the emulsion stability of sausage. The results indicated that Arg/Lys addition or increasing pH increased the emulsifying activity/stability index and the absolute ζ–potential of emulsion droplets but decreased the creaming index, apparent viscosity, and mean particle size of SSOE. Amino acid analysis showed that Arg/Lys accumulated at the interface of the emulsion droplets. Arg/Lys also decreased the surface tension of SWE at 0.002% but increased the stability of SWE at 0.1% – 0.3%. In summary, Arg/Lys improved the stability of emulsified sausage by increasing the electrostatic repulsion of emulsion droplets and decreasing the interfacial tension of soybean oil-water.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2011
·Vol. 173
·期 1
·241-247
·
IF 2.578
Fan Yang,Liu Jin-Hang,Lu Hai-Ting,Zhang Qin
We describe a glassy carbon electrode (GCE) modified with a film composed of Nafion and TiO 2 -graphene (TiO 2 -GR) nanocomposite, and its voltammetric response to the amino acids L-tryptophane (Trp) and L-tyrosine (Tyr). The incorporation of TiO 2 nanoparticles with graphene significantly improves the electrocatalytic activity and voltammetric response compared to electrodes modified with Nafion/graphene only. The Nafion/TiO 2 -GR modified electrode was used to determine Trp and Tyr with detection limits of 0.7 and 2.3 μM, and a sensitivity of 75.9 and 22.8 μA mM −1 for Trp and Tyr, respectively.
The electrochemical sensor based on Nafion/TiO 2 -GR composite film modified GCE was presented. The integration of TiO 2 nanoparticles with graphene provides an efficient microenvironment to promote the electrochemical reaction of amino acids Trp and Tyr. The fabricated electrochemical sensor exhibits favorable analytical performance for Trp and Tyr, with high sensitivity, low detection limit and good reproducibility.
研究领域:
电化学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Food Bioscience
·
2024
·
IF 4.8
Jiaxuan Wang,Cuiping Pang,Zhonglin Tu,Jianghua Li,Guocheng Du,Guoqiang Zhang
L-Alanyl- l -Glutamine (Ala-Gln) is a kind of functional dipeptide , which is widely used in food and health care. Ala-Gln can be synthesized from l -glutamine and l -alanine methyl ester hydrochloride by α-Amino acid ester acyltransferase (AET). Still, the low catalytic efficiency and conversion rate of AET are key limiting factors in Ala-Gln production. In this study, the mutant library of AET were built based on structural model and semi-rational design. To facilitate the screening of AET mutants, the double enzymes coupled screening method was constructed and optimized. The amino acid residues I115, D203, F211, D300, A298, and R334 were selected as candidate mutation sites by alanine scanning and virtual saturation mutation and the catalytic activity of the optimal mutation A298C increased by 23.7%. Molecular dynamics simulation and molecular docking analysis suggested that the increased flexibility of the catalytic pocket in AET (A298C) and the formation of additional hydrogen bonds with substrate contributed to the improvement of enzyme activity .
研究领域:
生物化学
·
酶工程
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
Microbial Cell Factories
·
2019
·Vol. 18
·期 1
·1-12
·
IF 4.402
Li Yi-Min,Gao Jiao-Qi,Pei Xu-Ze,Du Cong,Fan Chao,Yuan Wen-Jie,Bai Feng-Wu
Background l-Alanyl-l-glutamine (Ala-Gln) represents the great application potential in clinic due to the unique physicochemical properties. A new approach was developed to synthesize Ala-Gln by recombinant Escherichia coli OPA, which could overcome the disadvantages of traditional chemical synthesis. Although satisfactory results had been obtained with recombinant E. coli OPA, endotoxin and the use of multiple antibiotics along with toxic inducer brought the potential biosafety hazard for the clinical application of Ala-Gln.Results In this study, the safer host Pichia pastoris was applied as an alternative to E. coli. A recombinant P. pastoris (named GPA) with the original gene of α-amino acid ester acyltransferase (SsAet) from Sphingobacterium siyangensis SY1, was constructed to produce Ala-Gln. To improve the expression efficiency of SsAet in P. pastoris, codon optimization was conducted to obtain the strain GPAp. Here, we report that Ala-Gln production by GPAp was approximately 2.5-fold more than that of GPA. The optimal induction conditions (cultivated for 3 days at 26 °C with a daily 1.5% of methanol supplement), the optimum reaction conditions (28 °C and pH 8.5), and the suitable substrate conditions (AlaOMe/Gln = 1.5/1) were also achieved for GPAp. Although most of the metal ions had no effects, the catalytic activity of GPAp showed a slight decrease in the presence of Fe3+ and an obvious increase when cysteine or PMSF were added. Under the optimum conditions, the Ala-Gln generation by GPAp realized the maximum molar yield of 63.5% and the catalytic activity of GPAp by agar embedding maintained extremely stable after 10 cycles.Conclusion sCharacterized by economy, efficiency and practicability, production of Ala-Gln by recycling immobilized GPAp (whole-cell biocatalyst) is represents a green and promising way in industrial.
研究领域:
生物技术
·
酶学
·
药物化学
·
合成生物学
✓ 已验证
DOI
PubMed
高影响因子
Analytical Methods
·
2018
·Vol. 10
·期 19
·2263-2271
·
IF 2.073
Yunmei Huang,Jidong Yang,Haiyan Yuan,Yuan Guo,Xiaoqing Zeng,Jiawei Cheng,Yuhui Zhang
D-Penicillamine (D-PA), as the dominant enantiomer, is usually used in many clinical drugs, but the other enantiomer, L-penicillamine (L-PA) is a toxic enantiomer. Therefore, it is of great significance to analyze and detect L-PA in biomedical or environmental samples. CdTe quantum dots (CdTe QDs) were modified by N-acetyl-L-cysteine (NALC) as novel fluorescent probes and were successfully utilized for the determination of L-penicillamine. The fluorescence of the CdTe QDs decreased significantly in the presence of cupric ions (Cu2+) due to the binding of Cu2+ to NALC on the surface of the CdTe QDs, but the addition of L-PA immediately resulted in efficient fluorescence recovery of the modulated CdTe QDs. The experimental results showed that the pH of the buffer solution and the concentration of Cu2+ affected the fluorescence intensity upon adding L-PA. Under the optimum conditions, the recovered fluorescence intensity was linearly proportional to the increasing L-PA concentration in the range of 2 × 10−7 to 4 × 10−6 mol L−1, with correlation coefficient R2 = 0.9980. So, a new, simple and rapid method for the determination of L-PA has been developed and its potential has been demonstrated in human serum samples and environmental samples with satisfactory results.
研究领域:
分析化学
·
生物医学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
PROCESS BIOCHEMISTRY
·
2023
·
IF 4.4
Haidong Teng,Kaitong Chen,Lan Wang,Jianping Wu,Gang Xu
l -syn-3-[4-(methylsulfonyl)] phenylserine is a key industrial intermediate for the synthesis of florfenicol, thiamphenicol , and other products. l -Threonine aldolase can synthesize l -syn-3-[4-(methylsulfonyl)] phenylserine from glycine and 4-methylsulphonyl benzaldehyde directly. However, the selectivity of free l -threonine aldolase was difficult to meet the requirement of industrialization. Here, we selected the suitable site to insert His tag as immobilized site to improve the selectivity of l -threonine aldolase based on the molecular dynamics simulation and prior protein engineering. The phenanthroline was coupled to the surface of magnetic nanoparticles coated with silicon and thus enabled the selective and oriented immobilization of His-tagged l -threonine aldolase. Due to magnetic nanoparticles coated with silicon as supports, it was easy to separate the residual reactant and impurities from the immobilized enzyme by magnetic attraction. Moreover, the immobilization was combined with the purification of free enzymes through directional immobilization, which avoided heterozyme linking supports and improved the utilization efficiency of supports. Our study demonstrates an effective approach: how to analyze and select enzyme-targeted ligation sites in conjunction with previous modifications of engineered bacteria, and the immobilized enzyme obtained also provided a good candidate for the industrial production of l -syn-3-[4-(methylsulfonyl)] phenylserine.
研究领域:
生物化学
·
酶工程
·
纳米生物学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 1
·202
·
IF 5.3
Jingyu Li,Yang Zhang,Haichao Zhao,Guoxin Sui
The excessively leached metal ions from traditional metallic antimicrobial nanoparticles are harmful to biological and human tissues. Metal-organic frameworks (MOFs) coordinating bioactive metal ions to organic bridging ligands can potentially address this issue, avoiding the excessive leaching of metal ions and simultaneously exhibiting high effective antibacterial activities. Here, we report the preparation of a 2-dimensional leaves-like zeolitic imidazolate framework (ZIF-L) for potential antibacterial and anti-algae applications. The ZIF-L nanosheet exhibits complete inactivation ofEscherichia coli(phosphate buffer saline: 4 h) andBacillus subtilis(seawater: 0.5 h). The ZIF-L/epoxy composite has excellent antibacterial effect, poisoning effect and anti-adhesion effect on a variety of marine algae. It is worth noting that the removal rate (Escherichia coli) for ZIF/epoxy composite can be reached to 90.20% by only adding ZIF-L (0.25 wt%). This work will inspire researchers to develop more metal-organic frameworks materials for applications in the antibacterial and anti-algae fields.Keywords:ZIF-L;two dimensional;antibacterial;anti-algae
研究领域:
材料科学
·
生物医学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2020
·Vol. 28
·期 3
·884-891
·
IF 2.572
Wanyan Qianru,Qiu Yaxin,Xie Wenyuan,Wu Defeng
Poly( l -malic acid) (PLMA) oligomer was used as the minor phase to prepare the blends with poly( l -lactic acid) (PLLA), with the objective to develop fully biomass-derived and biodegradable aliphatic polyester blends with balanced overall performance. The phase behavior and viscoelastic responses reveals that the two phases are thermodynamically immiscible, showing high level of interfacial tension in their blends. Poor phase adhesion and lower mass weight of PLMA results in an evident decrease of mechanical properties of the blends as compared to PLLA. The dilute effect caused by the addition of PLMA, however, promotes the cold crystallization of PLLA. Therefore, the strength and modulus losses of the blends can be remedied well by the annealing in solid state. Besides, the degradation rates can also be regulated by the presence of hydrophilic PLMA phase. In this case, a fully green PLLA/PLMA blend with balanced properties is fabricated. This work also provides useful information developing new applications of PLMA.
研究领域:
材料科学
·
生物技术
·
高分子科学
·
可持续材料
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Mengna Li,Weiwang Qiu,Qian Wang,Na Li,Xueli Wang,Jianyong Yu,Xiaoran Li,Faxue Li,Dequn Wu
Bacterial biofilm often exists in non-healing wounds, and if it cannot be removed promptly, further complications will occur. Bioactive biodegradable wound dressings with the ability to kill bacteria, eliminate biofilms and prevent infections are expected to solve this problem. This study reports the development of a new l -tryptophan and l -phenylalanine-based poly(ester urea)s which aims at fabricating electrospun composite mat with nitric oxide releasing capability for infected wound treatment. The designed l -tryptophan and l -phenylalanine based poly(ester urea)s owned adjustable degradability and good biocompatibility , indicating it could be an ideal biomaterial for wound repair. The electrospun mat was an ideal cargo for steady and continuous delivery with a total concentration of 0.8 μmol/L of NO. The mats showed obvious advantages in killing the bacteria and destructing biofilms. Such electrospun mats could promote proliferation and improve collagen deposition as well as accelerate wound healing. It suggests that the fabric mats can act as a suitable candidate in infected-wound care applications.
研究领域:
材料科学
·
生物医学工程
·
伤口护理
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Xue Xia,Yun Zhai,Heping Cui,Han Zhang,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
The Amadori compound of glucose and l -alanyl- l -glutamine (Ala-Gln-ARP) was prepared and characterized by UPLC-MS/MS and NMR. There were no pyrazines produced by heated Ala-Gln-ARP alone due to the asynchronicity of regenerated l -alanyl- l -glutamine and α -dicarbonyl compounds. High temperature (130 °C) and long reaction time could facilitate the 2,5-dimethylpyrazine formation at a small concentration (33.4 ± 3.47 μg/L). The exogenous amino substrates would lower the formation temperature of pyrazines and make it to be generated effectively. Extra supplied l -alanyl- l -glutamine could generate 2,5-dimethylpyrazine at 110 °C, while higher temperature of 140 °C could strengthen the formation of 2,5-dimethylpyrazine (793 ± 119 μg/L) and stimulate the generation of other pyrazines, including methylpyrazine and 2,6-dimethylpyrazine. The exogenous alanine, glutamic acid, and glutamine was also beneficial to enhance the pyrazines formation, especially the glutamic acid. Furthermore, alkaline pH of thermal reaction made pyrazines increase significantly than in neutral medium and further enriched their species such as unsubstituted pyrazine and trimethylpyrazine.
研究领域:
食品化学
·
有机化学
·
分析化学
✓ 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）