BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple b...BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.展开更多
Nickel ferrite(NiFe_2O_4) nanoparticles have been dispersed in chitosan solution in order to fab ricate nanocomposite films.Horseradish peroxidase(HRP) has been immobilized onto this chitosan NiFe_2O_4 nanocomposite f...Nickel ferrite(NiFe_2O_4) nanoparticles have been dispersed in chitosan solution in order to fab ricate nanocomposite films.Horseradish peroxidase(HRP) has been immobilized onto this chitosan NiFe_2O_4 nanocomposite film via physical adsorption.The size of the NiFe_2O_4 nanoparticles has been estimated us ing X ray diffraction pattern and scanning electron microscopy(SEM) to be 40±9 nm.The chitosan NiFe_2O_4 nanocomposite film and HRP/chitosan NiFe_2O_4 bioelectrode have been characterized using SEM technique.The HRP/chitosan NiFe_2O_4 nanocomposite bioelectrode has a response time of 4 s,linearity as 0.3 to 12 m M of H2O2,sensitivity as 22 n A/m M.The effects of p H and the temperature of the immobilized HRP electrode have also been studied.展开更多
The activity of horseradish peroxidase at b-cyclodextrin polymer was imaged by scanning electrochemical microscopy using 3, 3’, 5, 5’-tetramethylbenzide and H2O2 as the substrates.
Objective To observe the inhibition and radiation-sensitizing effect of Indoleacetic acid (IAA) combined with horseradish peroxidase(HRP)on Hela cells. Methods Hela cells were cultured in vitro and classified into con...Objective To observe the inhibition and radiation-sensitizing effect of Indoleacetic acid (IAA) combined with horseradish peroxidase(HRP)on Hela cells. Methods Hela cells were cultured in vitro and classified into control group, drug group incubated with different doses of IAA(30, 60, 90μmol·L -1) plus 1.2μg·mL -1 HRP, radiation group (6MV-X, 4Gy ) and group of radiation plus IAA plus HRP(same dose as above). All the above were treated for 24-96 hours.The growth inhibition, radiation-sensitizing effect were observed with methyl thiazolyl tetrazolium (MTT) photocolorimetric assay and trypan blue dye assay. The-effect on cell proliferation cycle was determined by flow cytometry. Results The antiproliferation activities showed a significant time-effect and dose-effect relationship to some extent after Hela cells were treated with IAA combined with HRP. The group of radiation plus 60μmol·L -1 IAA plus 1.2μg·mL -1 HRP and radiation plus 90μmol·L -1 IAA plus 1.2μg·mL -1 HRP showed an obvious radiation sensitizing effect. After treatment with 90μmol·L -1 IAA plus 1.2 μg·mL -1 HRP for 72 hours, the determination of cell cycle showed that the percentages of the cells on stages G 2-M and S were all higher than those of the control group. For the group of radiation plus IAA combined with HRP, the percentages of the cells on stages G 2-M were higher than those of the radiation group. Conclusion The above findings suggest that IAA combined with HRP has an inhibitive and killing effect on Hela cells. The effect was stronger during the cell cycles of G 2-M and S. It also has a radiation sensitizing effect. Its mechanism might be that Hela cells were blocked on stages G 2-M, and it presents a collaborative killing effect during miototic time.展开更多
AIM: To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid (TAA) in combination with horseradish peroxidase (HRP).METHODS: BXPC-3 cells derived from...AIM: To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid (TAA) in combination with horseradish peroxidase (HRP).METHODS: BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, MTT assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were measured by biochemical methods.RESULTS: IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰,which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals.CONCLUSION: The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.展开更多
Direct electrochemistry and electrocatalysis of horseradish peroxidase(HRP) were achieved by entrapping the enzyme between CaCO3 microspheres and gold nanoparticles through forming sandwich configuration (CaCO3-HRP-Au...Direct electrochemistry and electrocatalysis of horseradish peroxidase(HRP) were achieved by entrapping the enzyme between CaCO3 microspheres and gold nanoparticles through forming sandwich configuration (CaCO3-HRP-AuNPs). Polyanion, poly(styrene sulfonate)(PSS), was hybrid with CaCO3 microspheres to increase the surface negative charges for binding with HRP through electrostatic interaction. After the bioconjugate CaCO3 PSS-HRP was entrapped in chitosan based sol-gel(CS-GPTMS) film, HRP was encapsulated by in situ formation of an outer layer of AuNPs through electrochemical reduction of HAuCl4. The composite film containing AuNPs, CaCO3-PSS-HRP bioconjugates and CS-GPTMS can provide favorable microenvironment for HRP to perform direct electron transfer at glassy carbon electrode(GCE). HRP retained its bioelectrocatalytic activity and lead to sensitive and fast amperometric response for the determination of H2O2. H2O2 could be detected in a very wide linear range from 5.0×10-6 mol/L to 7.1×10-2 mol/L. The sandwich configuration of CaCO3-biomolecules-AuNPs could serve as a versatile platform for enzyme immobilization and biosensing.展开更多
Objective To investigate the mechanisms of apoptosis induced in Human leukemia cell line K562 by the combination of indole-3-acetic acid and horseradish peroxidase.Methods Human leukemia cell line K562 were exposed to...Objective To investigate the mechanisms of apoptosis induced in Human leukemia cell line K562 by the combination of indole-3-acetic acid and horseradish peroxidase.Methods Human leukemia cell line K562 were exposed to indole-3-acetic acid（IAA） at 20,40,60,80 or 100mol/L and horseradish peroxidase（HRP） at 1.2g/mL for varying times.MTT assay was applied to detect the cell proliferation.Flow cytometry was performed to detect the arrest of cell cycle.Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling（TUNEL） assay was used to measure apoptosis.2,7-dichlorofluorescin diacetate（DCFH-DA） uptake was measured to determine free radical by confocal microscope.Content of malondiadehyde（MDA） and activity of superoxide dismutase（SOD） were measured by biochemical methods.Results IAA/HRP initiated growth inhibition of K562 cells in a dose-and time-dependent manner.Flow cytometry revealed that cell cycle arrested at G1/G0 after 24 hours treatment.After 72 hours treatment,apoptotic rate of 100 mol/L IAA group increased to 43.9%,which was 5 times that of control（P<0.01）.Content of MDA and activity of SOD increased respectively in treatments compared with control.Meanwhile,IAA/HRP stimulated the formation of free radical,which was increased by IAA concentration-dependently.Conclusion The combination of IAA and HRP can inhibit the growth of Human leukemia cell line K562 in vitro by inducing apoptosis which is associated with the increase of free radical.The combination of IAA and HRP might be a promising chemopreventive and chemotherapeutic agent against human leukemia.展开更多
Horseradish peroxidase (HRP) is generally used as a label enzyme in enzyme immunoassay (EIA).The procedure used for HRP detection in EIA is critical for sensitivity and precision.This paper describes a novel fluorimet...Horseradish peroxidase (HRP) is generally used as a label enzyme in enzyme immunoassay (EIA).The procedure used for HRP detection in EIA is critical for sensitivity and precision.This paper describes a novel fluorimetric assay for horseradish peroxidase (HRP) using sesamol as substrate.The principle of the assay is as follow:sesamol (3,4-methylenedioxy phenol) is reacted enzymatically in the presence of hydrogen peroxide to produce dimeric sesamol.The dimer is fluorescent and can be detected sensitively at ex.347 nm,em.427 nm.The measurable range of HRP was 1.0×10-18 to 1.0×10-15 mol/assay,with a detection limit of 1.0×10-18 mol/assay.The coefficient of variation (CV,n=8) was examined at each point on the standard curve,with a mean CV percentage of 3.8%.This assay system was applied to thyroid stimulating hormone (TSH) EIA using HRP as the label enzyme.展开更多
An electrochemical method for determination of horseradish peroxidase (HRP) was developed using a capillary catalytic system. HRP can be measured in several minutes with a detection limit of 4.8×10-12 mol/L or 47...An electrochemical method for determination of horseradish peroxidase (HRP) was developed using a capillary catalytic system. HRP can be measured in several minutes with a detection limit of 4.8×10-12 mol/L or 47 zmol (S/N=3).展开更多
An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by mi...An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by microencapsulation in a sol-gel film derived from tetraethyl orthosilicate(TEOS). The calibration plots for glucose were established by the optical fiber glucose sensor fabricated by attaching the bienzyme silica gel onto the glass window of the fiber bundle. The linear range was 0 2-2 mmol/L and the detection limit was approximately 0 12 mmol/L. The relative standard deviation was 5.3% ( n =6). The proposed biosensor was applied to glucose assay in ofloxacin injection successfully.展开更多
The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of β- cyclodextrin. During this course, β- cyclodextrin played a role of stabilizing the intermediates of HRP The results have been inve...The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of β- cyclodextrin. During this course, β- cyclodextrin played a role of stabilizing the intermediates of HRP The results have been investigated using spectra and calculation.展开更多
Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identifie...Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion, the ultimate carcinogens, which could bind to DNA. The reaction conditions were investigated preliminarily. Some inhibitors and inducers of the reaction were discovered.展开更多
Maize tassel-multiwalled carbon nanotube (MT-MWCNT) composite has been used as a matrix for physical adsorption of horseradish peroxidase (HRP) onto the surface of a glassy carbon electrode through electrostatic inter...Maize tassel-multiwalled carbon nanotube (MT-MWCNT) composite has been used as a matrix for physical adsorption of horseradish peroxidase (HRP) onto the surface of a glassy carbon electrode through electrostatic interactions. The HRP/MT-MWCNT biosensor was applied for the detection of Zn2+ in aqueous solution. The biosensor designed was able to determine Zn2+ in the range of 0.35 - 12 mg/L with a detection limit of 7.5 μg/L. The inhibition was found to be reversible and uncompetitive when data were modeled using the Dixon and Cornish-Bowden plots. The biosensor was found to have good repeatability, reproducibility and high selectivity. The developed biosensor can be used to detect other HRP inhibiting trace metal ions.展开更多
Horseradish peroxidase, an acidic peroxidase from the horseradish, is one of the most important enzymes as analytical reagent. The enzymatic nitration of phenol by oxidation of nitrite was studied using horseradish pe...Horseradish peroxidase, an acidic peroxidase from the horseradish, is one of the most important enzymes as analytical reagent. The enzymatic nitration of phenol by oxidation of nitrite was studied using horseradish peroxidase in the presence of H2O2. The results showed that nitration occur at 2- and 4- positions of phenol. There were also minor products of hydroquinone and catechol. The influence of various reaction parameters, including pH, organic solvent, and concentration of H2O2, on nitration products were discussed. The best nitration pH was 7.0, and H2O2 should be added to the reaction mixture slowly.展开更多
A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by e...A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by electrochemical and spectroscopic techniques. Results showed that the immobilized HRP exhibited direct electrochemical behavior toward the reduction of H2O2. The resulting biosensor shows a fast amperometric response (<2 s) to H2O2. The linear response range was from 5.0×10-7～1.0×10-5 mol/L with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor has a good reproducibility, and long-term stability.展开更多
It is reported for the first time that horseradish peroxidase (HRP) immobilized on the active carbon can undergo a direct quasi-reversible electrochemical reaction.In addition,the immobilized HRP showed the stable bio...It is reported for the first time that horseradish peroxidase (HRP) immobilized on the active carbon can undergo a direct quasi-reversible electrochemical reaction.In addition,the immobilized HRP showed the stable bioelectrocatalytic activity for the reduction of H2O2.展开更多
A novel hydrogen peroxide biosensor has been fabricated based on covalently linked horseradish peroxidase(HRP)onto L- glutathione self-assembled monolayers(SAMs).The SAMs-based electrode was characterized by electroch...A novel hydrogen peroxide biosensor has been fabricated based on covalently linked horseradish peroxidase(HRP)onto L- glutathione self-assembled monolayers(SAMs).The SAMs-based electrode was characterized by electrochemical methods,and direct electrochemistry of HRP can be achieved with formal potential of-0.242 V(vs.saturated Ag/AgCl)in pH 7 phosphate buffer solution(PBS),the redox peak current is linear to scan rate and rate constant can be calculated to be 0.042s^(-1).The HRP-SAMs- based biosensors show its better electrocatalysis to hydrogen peroxide in the concentration range of 1×10^(-6)mol/L to 1.2×10^(-3)mol/L with a detection limit of 4×10^(-7)mol/L.The apparent Michealis-Menten constant is 3.12 mmol/L.The biosensor can effectively eliminate the interferences of dopamine,ascorbic acid,uric acid,catechol and p-acetaminophen.展开更多
基金Supported by National Natural Science Foundation of China,No.82060123Doctoral Start-up Fund of Affiliated Hospital of Guizhou Medical University,No.gysybsky-2021-28+1 种基金Fund Project of Guizhou Provincial Science and Technology Department,No.[2020]1Y299Guizhou Provincial Health Commission,No.gzwjk2019-1-082。
文摘BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.
基金the Fatih University,Research Project Foundation (Contract no:P500209022)Scientific and Technological Research Council of Turkey (TBTAK) (Pro ject no:110T487)TURKEY Prime Ministry State Planning Organization
文摘Nickel ferrite(NiFe_2O_4) nanoparticles have been dispersed in chitosan solution in order to fab ricate nanocomposite films.Horseradish peroxidase(HRP) has been immobilized onto this chitosan NiFe_2O_4 nanocomposite film via physical adsorption.The size of the NiFe_2O_4 nanoparticles has been estimated us ing X ray diffraction pattern and scanning electron microscopy(SEM) to be 40±9 nm.The chitosan NiFe_2O_4 nanocomposite film and HRP/chitosan NiFe_2O_4 bioelectrode have been characterized using SEM technique.The HRP/chitosan NiFe_2O_4 nanocomposite bioelectrode has a response time of 4 s,linearity as 0.3 to 12 m M of H2O2,sensitivity as 22 n A/m M.The effects of p H and the temperature of the immobilized HRP electrode have also been studied.
文摘The activity of horseradish peroxidase at b-cyclodextrin polymer was imaged by scanning electrochemical microscopy using 3, 3’, 5, 5’-tetramethylbenzide and H2O2 as the substrates.
文摘Objective To observe the inhibition and radiation-sensitizing effect of Indoleacetic acid (IAA) combined with horseradish peroxidase(HRP)on Hela cells. Methods Hela cells were cultured in vitro and classified into control group, drug group incubated with different doses of IAA(30, 60, 90μmol·L -1) plus 1.2μg·mL -1 HRP, radiation group (6MV-X, 4Gy ) and group of radiation plus IAA plus HRP(same dose as above). All the above were treated for 24-96 hours.The growth inhibition, radiation-sensitizing effect were observed with methyl thiazolyl tetrazolium (MTT) photocolorimetric assay and trypan blue dye assay. The-effect on cell proliferation cycle was determined by flow cytometry. Results The antiproliferation activities showed a significant time-effect and dose-effect relationship to some extent after Hela cells were treated with IAA combined with HRP. The group of radiation plus 60μmol·L -1 IAA plus 1.2μg·mL -1 HRP and radiation plus 90μmol·L -1 IAA plus 1.2μg·mL -1 HRP showed an obvious radiation sensitizing effect. After treatment with 90μmol·L -1 IAA plus 1.2 μg·mL -1 HRP for 72 hours, the determination of cell cycle showed that the percentages of the cells on stages G 2-M and S were all higher than those of the control group. For the group of radiation plus IAA combined with HRP, the percentages of the cells on stages G 2-M were higher than those of the radiation group. Conclusion The above findings suggest that IAA combined with HRP has an inhibitive and killing effect on Hela cells. The effect was stronger during the cell cycles of G 2-M and S. It also has a radiation sensitizing effect. Its mechanism might be that Hela cells were blocked on stages G 2-M, and it presents a collaborative killing effect during miototic time.
基金Supported by the Natural Science Foundation of Shaanxi Province, No. 2003C215
文摘AIM: To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid (TAA) in combination with horseradish peroxidase (HRP).METHODS: BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, MTT assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were measured by biochemical methods.RESULTS: IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰,which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals.CONCLUSION: The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.
基金Supported by the National Natural Science Foundation of China(Nos.20775039, 20602009)the Natural Science Foundation of Shandong Province of China(No.ZR2009BM031)+3 种基金the Public Welfare Project of Marine Science Research, China(Nos. 200705011, 200805039)the Scientific Research Fund of the First Institute of Oceanographythe State Oceanic Administration of China(No.2010T04)the Science and Technology Project of Shandong Company of China National Tobacco Corpora-tion(No.KN172)
文摘Direct electrochemistry and electrocatalysis of horseradish peroxidase(HRP) were achieved by entrapping the enzyme between CaCO3 microspheres and gold nanoparticles through forming sandwich configuration (CaCO3-HRP-AuNPs). Polyanion, poly(styrene sulfonate)(PSS), was hybrid with CaCO3 microspheres to increase the surface negative charges for binding with HRP through electrostatic interaction. After the bioconjugate CaCO3 PSS-HRP was entrapped in chitosan based sol-gel(CS-GPTMS) film, HRP was encapsulated by in situ formation of an outer layer of AuNPs through electrochemical reduction of HAuCl4. The composite film containing AuNPs, CaCO3-PSS-HRP bioconjugates and CS-GPTMS can provide favorable microenvironment for HRP to perform direct electron transfer at glassy carbon electrode(GCE). HRP retained its bioelectrocatalytic activity and lead to sensitive and fast amperometric response for the determination of H2O2. H2O2 could be detected in a very wide linear range from 5.0×10-6 mol/L to 7.1×10-2 mol/L. The sandwich configuration of CaCO3-biomolecules-AuNPs could serve as a versatile platform for enzyme immobilization and biosensing.
基金This work was supported by the Natural Science Foundation of Shaanxi Province(No.2003C215).
文摘Objective To investigate the mechanisms of apoptosis induced in Human leukemia cell line K562 by the combination of indole-3-acetic acid and horseradish peroxidase.Methods Human leukemia cell line K562 were exposed to indole-3-acetic acid（IAA） at 20,40,60,80 or 100mol/L and horseradish peroxidase（HRP） at 1.2g/mL for varying times.MTT assay was applied to detect the cell proliferation.Flow cytometry was performed to detect the arrest of cell cycle.Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling（TUNEL） assay was used to measure apoptosis.2,7-dichlorofluorescin diacetate（DCFH-DA） uptake was measured to determine free radical by confocal microscope.Content of malondiadehyde（MDA） and activity of superoxide dismutase（SOD） were measured by biochemical methods.Results IAA/HRP initiated growth inhibition of K562 cells in a dose-and time-dependent manner.Flow cytometry revealed that cell cycle arrested at G1/G0 after 24 hours treatment.After 72 hours treatment,apoptotic rate of 100 mol/L IAA group increased to 43.9%,which was 5 times that of control（P<0.01）.Content of MDA and activity of SOD increased respectively in treatments compared with control.Meanwhile,IAA/HRP stimulated the formation of free radical,which was increased by IAA concentration-dependently.Conclusion The combination of IAA and HRP can inhibit the growth of Human leukemia cell line K562 in vitro by inducing apoptosis which is associated with the increase of free radical.The combination of IAA and HRP might be a promising chemopreventive and chemotherapeutic agent against human leukemia.
文摘Horseradish peroxidase (HRP) is generally used as a label enzyme in enzyme immunoassay (EIA).The procedure used for HRP detection in EIA is critical for sensitivity and precision.This paper describes a novel fluorimetric assay for horseradish peroxidase (HRP) using sesamol as substrate.The principle of the assay is as follow:sesamol (3,4-methylenedioxy phenol) is reacted enzymatically in the presence of hydrogen peroxide to produce dimeric sesamol.The dimer is fluorescent and can be detected sensitively at ex.347 nm,em.427 nm.The measurable range of HRP was 1.0×10-18 to 1.0×10-15 mol/assay,with a detection limit of 1.0×10-18 mol/assay.The coefficient of variation (CV,n=8) was examined at each point on the standard curve,with a mean CV percentage of 3.8%.This assay system was applied to thyroid stimulating hormone (TSH) EIA using HRP as the label enzyme.
基金the National Natural Science Foundation of China
文摘An electrochemical method for determination of horseradish peroxidase (HRP) was developed using a capillary catalytic system. HRP can be measured in several minutes with a detection limit of 4.8×10-12 mol/L or 47 zmol (S/N=3).
文摘An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by microencapsulation in a sol-gel film derived from tetraethyl orthosilicate(TEOS). The calibration plots for glucose were established by the optical fiber glucose sensor fabricated by attaching the bienzyme silica gel onto the glass window of the fiber bundle. The linear range was 0 2-2 mmol/L and the detection limit was approximately 0 12 mmol/L. The relative standard deviation was 5.3% ( n =6). The proposed biosensor was applied to glucose assay in ofloxacin injection successfully.
文摘The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of β- cyclodextrin. During this course, β- cyclodextrin played a role of stabilizing the intermediates of HRP The results have been investigated using spectra and calculation.
文摘Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds. The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion, the ultimate carcinogens, which could bind to DNA. The reaction conditions were investigated preliminarily. Some inhibitors and inducers of the reaction were discovered.
文摘Maize tassel-multiwalled carbon nanotube (MT-MWCNT) composite has been used as a matrix for physical adsorption of horseradish peroxidase (HRP) onto the surface of a glassy carbon electrode through electrostatic interactions. The HRP/MT-MWCNT biosensor was applied for the detection of Zn2+ in aqueous solution. The biosensor designed was able to determine Zn2+ in the range of 0.35 - 12 mg/L with a detection limit of 7.5 μg/L. The inhibition was found to be reversible and uncompetitive when data were modeled using the Dixon and Cornish-Bowden plots. The biosensor was found to have good repeatability, reproducibility and high selectivity. The developed biosensor can be used to detect other HRP inhibiting trace metal ions.
文摘Horseradish peroxidase, an acidic peroxidase from the horseradish, is one of the most important enzymes as analytical reagent. The enzymatic nitration of phenol by oxidation of nitrite was studied using horseradish peroxidase in the presence of H2O2. The results showed that nitration occur at 2- and 4- positions of phenol. There were also minor products of hydroquinone and catechol. The influence of various reaction parameters, including pH, organic solvent, and concentration of H2O2, on nitration products were discussed. The best nitration pH was 7.0, and H2O2 should be added to the reaction mixture slowly.
文摘A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by electrochemical and spectroscopic techniques. Results showed that the immobilized HRP exhibited direct electrochemical behavior toward the reduction of H2O2. The resulting biosensor shows a fast amperometric response (<2 s) to H2O2. The linear response range was from 5.0×10-7～1.0×10-5 mol/L with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor has a good reproducibility, and long-term stability.
文摘It is reported for the first time that horseradish peroxidase (HRP) immobilized on the active carbon can undergo a direct quasi-reversible electrochemical reaction.In addition,the immobilized HRP showed the stable bioelectrocatalytic activity for the reduction of H2O2.
文摘A novel hydrogen peroxide biosensor has been fabricated based on covalently linked horseradish peroxidase(HRP)onto L- glutathione self-assembled monolayers(SAMs).The SAMs-based electrode was characterized by electrochemical methods,and direct electrochemistry of HRP can be achieved with formal potential of-0.242 V(vs.saturated Ag/AgCl)in pH 7 phosphate buffer solution(PBS),the redox peak current is linear to scan rate and rate constant can be calculated to be 0.042s^(-1).The HRP-SAMs- based biosensors show its better electrocatalysis to hydrogen peroxide in the concentration range of 1×10^(-6)mol/L to 1.2×10^(-3)mol/L with a detection limit of 4×10^(-7)mol/L.The apparent Michealis-Menten constant is 3.12 mmol/L.The biosensor can effectively eliminate the interferences of dopamine,ascorbic acid,uric acid,catechol and p-acetaminophen.
