Marine Drugs
·
2023
·Vol. 21
·期 1
·47
·
IF 5.4
Xin-Nan Teng,Shu-Chang Wang,Liaqat Zeb,Yue-Sheng Dong,Zhi-Long Xiu
Antarctic krill is a crucial marine resource containing plenty of high-valued nutrients. However, krill oil as a single product has been developed by the current solvent extraction with high cost. From the perspective of comprehensive utilization of Antarctic krill, this study proposed a novel two-step enzymolysis-assisted extraction in attempt to produce value-added oil and enzymolysate simultaneously. After two-step chitinase/protease hydrolysis, the lipid yield increased from 2.09% to 4.18%, reaching 112% of Soxhlet extraction. The method greatly improved the yields of main components while reducing the impurity content without further refining. After optimization, the oil contained 246.05 mg/g of phospholipid, 80.96 mg/g of free eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and 0.82 mg/g of astaxanthin. The by-product enzymolysate was abundant in water-soluble proteins (34.35 mg/g), oligopeptides (13.92 mg/g), amino acids (34.24 mg/g), and carbohydrates (5.79 mg/g), which was a good source of functional nutrients. In addition, both oil and enzymolysate showed high antioxidant capacity. This novel method could simultaneously provide oil and enzymolysate amounting for 58.61% of dried krill.Keywords:Antarctic krill oil;enzymolysis;protease;chitinase;extraction
研究领域:
海洋生物学
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食品科学
·
生物技术
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DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Yusheng Gao,Guiqian Wang,Hongzhi Gu,Jinli Zhang,Wei Li,Yan Fu
Distinct Pt nanozymes can be cooperatively tuned by natural nucleotides and solvents. Ethylene glycol assists the nucleotide-mediated reduction of Pt(II) precursors together with the growth of Pt nanocrystals. The nanocrystals possess high proportion of metallic Pt 0 atoms, thereby contributing to considerable oxidase- and peroxidase-like activities. Nevertheless, ultrasmall Pt nanoclusters synthesized in water display cationic features on nanocluster surface, showing highly enzymatic selectivity toward peroxidase. The Pt nanocrystals also display laccase mimicking activity, which can be harnessed for colorimetric assay of epinephrine with high sensitivity. The linear detection range lies in 4.55−172.98 μM with the limit of detection of 0.66 μM. This work proposes a facile and effective methodology to tune both the catalytic activity and the enzymatic selectivity of metal nanozymes.
研究领域:
纳米技术
·
催化
·
生物化学
·
分析化学
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产品关联
DOI
高影响因子
ACS Biomaterials Science & Engineering
·
2019
·
IF 4.511
Sihui Chen,Yixian Wang,Mengxiao Zhong,Dahai Yu,Ce Wang,Xiaofeng Lu
In the past decade, nanomaterials-based artificial enzymes have emerged as a hot spot in the field of catalysis. However, it is a significant challenge to fabricate functional nanomaterials for multiple-enzyme mimetic activity. In this work, we have presented an efficient catalytic platform to mimic peroxidase, oxidase, and catalase-like activity by Fe3C decorated carbon nanofibers (Fe3C/C NFs). First, polyacrylonitrile nanofibers (PAN NFs) are prepared via an electrospinning technique. Next, an Fe(III)-tannic acid (TA) complex is formed on the surface of PAN NFs through a wet chemical reaction. Finally, Fe3C/C NFs are obtained from the carbonization of the PAN/Fe(III)-TA complex nanofibers. The prepared Fe3C/C NFs show an excellent triple-enzyme mimetic property including peroxidase-like, oxidase-like, and catalase-like activity, which is investigated thoroughly by the colorimetric experiment of the 3,3′,5,5′-tetramethyl benzidine oxidation and the degradation of H2O2. Thanks to the superior catalytic performance of Fe3C/C NFs for oxidase mimicking, a facile and colorimetric way to determine glutathione with a high sensitivity and favorable selectivity has been achieved. This work provides an efficient platform for multiple-enzyme mimicking, which may expand their promising applications in biosensing, biomedicine, and environmental technology.
研究领域:
材料科学
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生物医学
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环境科学
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Yuxi Guo,Xuefeng Chen,Pin Gong,Jing Guo,Dan Deng,Guanglian He,Chenglong Ji,Ruotong Wang,Hui Long,Jiating Wang,Wenbo Yao,Wenjuan Yang,Fuxin Chen
We investigated the browning and softening of fresh Lentinula edodes (LE) coated with polysaccharides (LEP) isolated from LE stalks and stored at 4 °C for 15 days. The results showed that compared to the chitosan-coated and uncoated LE, the LEP-treated mushrooms showed significant improvements in several qualities during storage, such as reduced weight loss, retention of hardness and springiness, improved soluble protein content, and reduced browning, malondialdehyde content, and electrolyte leakage rate. The best results were obtained with 1.5 % LEP. LEP improved the activities of peroxidase, catalase, superoxide dismutase, ascorbate peroxidase, and phenylalanine ammonialyase and significantly reduced the accumulation of hydrogen peroxide during storage compared to the control samples. In addition, the LEP treatment maintained the high antioxidant activity of LE during storage. Notably, LEP inhibited browning-related enzymes (polyphenol oxidase and tyrosinase) to reduce browning. It also maintained high levels of cellulase, chitinase, and β -1,3 glucanase to improve softening during storage. These findings suggest the potential of LEP to improve the post-harvest quality of mushrooms, allowing a storage period of up to 15 days (extending the shelf life by six days) and indirectly suggesting that the polysaccharide component of LEP can act as a self-defense additive to protect against spoilage during storage.
研究领域:
食品科学
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采后技术
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真菌学
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生物化学
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DOI
PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 103
·期 15
·6333-6344
·
IF 3.67
Ji Junbin,Zhang Ji,Liu Yongchuang,Zhang Yanting,Liu Yuanxin,Yan Xin
The residues of aniline and its derivatives are serious environment pollutants. Aniline dioxygenase (AD) derived from aerobic bacteria catalyzes the conversion of aniline to catechol, which has potential use in the bioremediation of aromatic amines and biorefining process. AD contains four components: a glutamine synthetase (GS)-like enzyme, a glutamine amidotransferase (GAT)-like enzyme, oxygenase, and reductase. ADs from diverse hosts exhibit different substrate specificities against aniline derivatives. However, what component of AD determines AD’s substrate specificity is still unknown which limits the effects of extending AD’s substrate spectrum through mutagenesis. Here, each component of two ADs (AtdA1A2A3A4A5 and AdoQTA1A2B) which have different substrate ranges was heterologously expressed and purified. The activity of both ADs was successfully constructed in vitro using the purified components. To identify the component that affects the substrate specificity of the ADs, the substrate specificity of each component was studied. The inability of AtdA1A2A3A4A5 to catalyze 4-methylaniline was determined with GS-like enzyme AtdA1; its inability to convert 2-isopropylaniline was caused by the oxygenase component, and its inability to convert 4-isopropylaniline was caused by both GS-like enzyme AtdA1 and oxygenase components. The inability of AdoQTA1A2B to catalyze 2-methylaniline was determined by GS-like enzyme AdoQ; its inability to convert 2-isopropylaniline was caused by both GS-like enzyme AdoQ and oxygenase components. Together, these results show that GS-like enzyme and oxygenase but not GAT-like enzyme or reductase play dominant roles in the substrate specificity of AD, and this finding will facilitate the engineering of AD to expand its substrate range.
研究领域:
环境科学
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微生物学
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分子生物学
✓ 已验证
DOI
PubMed
高影响因子
Polymers
·
2022
·Vol. 15
·期 1
·206
·
IF 4.967
Xushuo Yuan,Jiaxin Zhao,Xiaoxiao Wu,Wentao Yao,Haiyang Guo,Decai Ji,Qingkai Yu,Liwen Luo,Xiaoping Li,Lianpeng Zhang
This study explored a green and efficient method for cellulose extraction from corn bract. The cellulose extraction by the CHB (CH3COOH/H2O2/Bio-enzyme) method and the N-CHB (NH3·H2O-CH3COOH/H2O2/Bio-enzyme) method were compared and analyzed. The effect of ammonia pretreatment on cellulose extraction by bio-enzymatic methods was discussed. The results showed that ammonia promoted the subsequent bio-enzymatic reaction and had a positive effect on the extraction of cellulose. Sample microstructure images (SEM) showed that the cellulose extracted by this method was in the form of fibrous bundles with smooth surfaces. The effect of different pretreatment times of ammonia on cellulose was further explored, and cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric (TG) analysis. The results showed that the N3h-CHB (NH3·H2O 50 °C 3 h, CH3COOH/H2O270 °C 11 h, Bio-enzyme 50 °C 4 h) method was the best way to extract cellulose in this study. FTIR showed that most of the lignin and hemicellulose were removed. XRD showed that all the cellulose extracted in this study was type I cellulose. TG analysis showed that the cellulose was significantly more thermally stable, with a maximum degradation temperature of 338.9 °C, close to that of microcrystalline cellulose (MCC). This study provides a reference for the utilization of corn bract and offers a new technical route for cellulose extraction.Keywords:cellulose;bio-enzymes;corn bract;ammonia;pretreatment;ligninase;hemicellulase;pectinase
研究领域:
生物化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2024
·Vol. 41
·期 1
·1-12
·
IF 4
Li Yang-Nan,Zhu Chen-Yuan,Xu Chen-Lu,Yu Shen,Huan Tong,Zhang Ye-Wang
A heparinase III ( Ns Hep-III) from Niabella sp . was identified, cloned, and expressed as soluble form in E. coli BL21 (DE3). With heparin as substrate, the maximum activity of Ns Hep-III of 90.0 U·mg − 1 was achieved at pH 7.1 Tris-HCl (containing 15 mM Mg 2+ ) and 30 o C. The half-life of Ns Hep-III was determined to be 5 h at 30 o C. The interactions between Ns Hep-III and substrates were studied by molecular docking. The combination of Ns Hep-III and a heparinase I from Bacteroides eggthii ( Be Hep-I) was employed to cleave heparin. Analysis of the enzymatic products of Ns Hep-III by SAX-HPLC showed seven different modified disaccharides, indicating that Ns Hep-III has a wide range of substrate specificity. The results of GPC analysis demonstrated that the average molecular weight of the product of heparin cleavage by the combination of Ns Hep-III/ Be Hep-I was reduced to 3969 Da, which accounted for 90% of all the components, and complied with the requirements of the European Pharmacopoeia. Ns Hep-III has notable activity and efficiency in cleaving heparin, which is potentially useful for the industrial production of low molecular weight heparin.
研究领域:
生物化学
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药学
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产品关联
DOI
PubMed
高影响因子
MOLECULAR MICROBIOLOGY
·
2021
·Vol. 116
·期 3
·783-793
·
IF 3.501
Yidong Zhou,Siyuan Gao,Mingliang Zhang,Wankui Jiang,Zhijian Ke,Jiguo Qiu,Jianhong Xu,Qing Hong
Salicylate is a typical aromatic compound widely distributed in nature. Microbial degradation of salicylate has been well studied and salicylate hydroxylases play essential roles in linking the peripheral and ring-cleavage catabolic pathways. The direct hydroxylation of salicylate catalyzed by salicylate-1-hydroxylase or salicylate-5-hydroxylase has been well studied. However, the CoA mediated salicylate 5-hydroxylation pathway has not been characterized in detail. Here, we elucidate the molecular mechanism of the reaction in the conversion of salicylate to gentisate in the carbaryl-degrading strain Rhizobium sp. X9. Three enzymes (salicylyl-CoA ligase CehG, salicylyl-CoA hydroxylase CehH and gentisyl-CoA thioesterase CehI) catalyzed the conversion of salicylate to gentisate via a route, including CoA thioester formation, hydroxylation and thioester hydrolysis. Further analysis indicated that genes cehGHI are also distributed in other bacteria from terrestrial environment and marine sediments. These genomic evidences highlight the role of this salicylate degradation pathway in the carbon cycle of soil organic compounds and marine sediments. Our findings of this three-step strategy enhanced the current understanding of CoA mediated degradation of salicylate.
研究领域:
微生物学
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环境科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
CRYOLETTERS
·
2023
·Vol. 44
·期 5
·280-290
·
IF 1
Wu Jiawei,Liu Yeyu,Zhang Jinping,Wang Xiaohui
BACKGROUND: Chitin is the second largest carbon source on the earth, and chitosan oligosaccharides produced by its degradation have good application prospects in medicine, cosmetics, and agricultural production. OBJECTIVE: The discovery of a chitinase with high efficiency,
high stability and clear degradation mechanism is of great help to promote the research of chitin derivatives and the development of the industrial chain. MATERIALS AND METHODS: In this experiment, a lowtemperature chitinase-producing strain Photobacterium sp. LG-29 was isolated
from deep-sea mud in the Bohai Sea, and studied by means of molecular biology, biochemistry and bioinformatics. RESULTS: Purification of chitinase yielded an enzyme solution with a concentration of 0.918 mg/mL and a specific activity of 21.036 U/mg. The optimum action temperature is
35°C, and it is still active at 4°C, showing low-temperature enzymatic activity, and also has certain thermal stability. The optimum pH is 8.0, and it maintains more than 70% of the enzyme activity at pH 11, which is very stable in an alkaline environment. Mn2+, Ca2+,
and Mg2+ are the main activators of enzymes, while Fe2+, Zn2+, etc. have extremely significant inhibitory effects on enzymes. The Km and Kcat of chitinase were determined to be 269.05 μ mol/L and 0.49 min-1, respectively. Chitinase PbCHI5 has
both endonuclease and exonuclease activity. The theoretical pI of the enzyme is 4.16, which is a stable hydrophilic protein. CONCLUSION: This experiment laid a theoretical foundation for the development and utilization of new low-temperature chitinases.
研究领域:
分子生物学
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生物化学
·
生物信息学
·
酶学
·
海洋微生物学
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DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Guangxia Jin,Jie Liu,Chan Wang,Wenxiu Gu,Guoxia Ran,Bing Liu,Qijun Song
An enzyme-like nanoplatform obtained from sodium citrate-modified iridium nanoparticles (Cit-IrNPs) was presented, which exhibits excellent peroxidase, catalase and oxidase like activities thanks to the large accessible surface area and high-index facets of the mono-dispersed nanoparticles. The morphology and structures of Cit-IrNPs were comprehensively characterized by TEM, HRTEM, XRD, IR and XPS. The surface chemistry of Cit-IrNPs reveals that the oxidase-like and peroxidase-like activities can be ascribed to the formation of O 2 ¯ from the activation of dissolved oxygen on the high-index facets of IrNPs. The oxidase-like activity of Cit-IrNPs was further manifested by the oxidation of 33.3 mM aromatic alcohols in the presence of 3 mg/mL Cit-IrNPs in ambient conditions. Over 90 % conversion rates were readily obtainable in 10 h for all the tested alcohols with an initial reaction rate of ca. 20 μmol/h. More significantly, apart from the aldehydes no other byproducts were detected. The kinetic analysis of the enzyme mimic suggests the reaction follows a classical Michaelis-Menten model. The enzyme mimic also shows a good stability, as no obvious decrease in catalytic activity was observed after recycled use for 6 times. Furthermore, DFT calculation was employed to elucidate the reaction mechanism and it was found that the alcohol is initially bond to Ir(0) and subsequently forms Ir δ + -alkoxide species and the carbonyl product. Meanwhile, the Ir δ + -hydride species reductively eliminates O 2 ¯ and returns back to Ir(0). To the best of our knowledge, this is the first report of metal nanomaterials which can effectively transform aromatic alcohols to corresponding aldehydes at ambient conditions without need of external energy input.
研究领域:
生物化学
·
纳米生物学
·
催化科学
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产品关联
DOI
高影响因子
BIOCHEMISTRY
·
2018
·
IF 2.997
Qianwei Zhao,Wen Yang,Tong Qin,Zhen Huang
RNA is a key player in the cellular central dogma, including RNA transcription and protein synthesis. However, it is unknown whether RNA can directly interfere with DNA synthesis. Recently, we have found in vitro that while binding to DNA polymerase nonspecifically, RNA can transform DNA polymerase to display a moonlighting activity, dNTP phosphatase, in turn interfering with DNA synthesis. This phosphatase activity removes the γ-phosphate from dNTPs (generating dNDPs) and subsequently removes the β-phosphate from the formed dNDPs (generating dNMPs), confirmed by the noncleavable α,β-CH2-dGTP and β,γ-CH2-dGTP analogues. We also found that dGTP is the best substrate for the phosphatase, and the dNTP phosphatase activity is sensitive to the reaction medium. In addition, we have revealed that RNA can tune the activity of closely related proteins and give rise to new catalytic functions with subtle differences. Moreover, we have demonstrated in vitro that at the lower dNTP level, this phosphatase can directly inhibit DNA synthesis by dNTP depletion, though the phosphatase activity is 690-fold slower than the polymerase activity. Our observation in vitro suggests a plausible strategy for RNA to directly interfere with DNA polymerase and DNA synthesis in vivo.
研究领域:
分子生物学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Zhejiang University-SCIENCE B
·
2018
·
IF 1.815
Lei Yuan,Faizan A. Sadiq,Tong-jie Liu,Yang Li,Jing-si Gu,Huan-yi Yang,Guo-qing He
The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia , Pseudomonas , Serratia , and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter , and the highest in Acinetobacter guillouiae . Certain isolates showed positive β-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.
研究领域:
食品科学
·
微生物学
✓ 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）