Fluorescence decrease ratio was applied to determine of arte misinin （qinghaosu, QHS） based on the catalytic effect of hemoglobin （Hb） using tetraethyldiaminoxanthenyl chloride （Pryonine B, PB） as monitor in thi...Fluorescence decrease ratio was applied to determine of arte misinin （qinghaosu, QHS） based on the catalytic effect of hemoglobin （Hb） using tetraethyldiaminoxanthenyl chloride （Pryonine B, PB） as monitor in this work, Experimental results show that the catalytic characteristics of Hb for QHS, being expressed as Michaelis-Menten parameters, Km, Vmax and Kcat are 2.8×10^-5 mol·L^-1, 4.2×10^-5 mol·L^-1·s^-1 and 280 s^-1 , respectively. Like hemin, enzymatic bioactivities of Hb is inhibited by both deactivated agents and high temperature whereas enhanced by ethanol. With the catalytic action of Hb, quantitative method of QHS can be established based on the fluorescence decrease of PB and linear relationship between the fluorescence decrease ratio F0/F and the concentration of QHS is in the range of （0.0-1.1）×10^-6 mol·L^-1 with detection limit （3σ） being 7. 2×10^-9 mol·L^-1, The concentration of QHS in the media of plasma or urine was detected using this method.展开更多
Fluorescence decrease ratio （F0/F） was applied to determination of artemisinin （qinghaosu, QHS） based on the catalytic effect of tyrosinase using tetraethyldiaminoxanthenyl chloride （pyronine B, PB） as monitor. ...Fluorescence decrease ratio （F0/F） was applied to determination of artemisinin （qinghaosu, QHS） based on the catalytic effect of tyrosinase using tetraethyldiaminoxanthenyl chloride （pyronine B, PB） as monitor. A catalyst used commonly in the decomposition of QHS, tyrosinase, exhibited higher binding activity than hemin, which was expressed as Michaelis-Menten parameters, km, Vmax, and kcat respectively. Interaction of QHS with tyrosinase was inhibited in the presence of deactivating agents at high temperature whereas enhanced by ethanol. Under optimal conditions, a concentration of 1.4×10^-7-8.4×10^-7 mol·L^-1of QHS could be determined on the basis of fluorescence decrease ratio of PB, with a detection limit 3tr of 2.6×10^-9 mol·L^-1. The proposed method was applied to detection of the concentration of QHS in the media of plasma and urine.展开更多
Enzyme-catalytic fluorescence determination of artemisinin (qinghaosu, QHS) was developed using pyronine B (PB) as substrate of horseradish peroxidase (HRP). The interaction between HRP and QHS was an enzyme-substrate...Enzyme-catalytic fluorescence determination of artemisinin (qinghaosu, QHS) was developed using pyronine B (PB) as substrate of horseradish peroxidase (HRP). The interaction between HRP and QHS was an enzyme-substrate model. The catalytic characteristic of HRP in the oxidation reaction, in which the fluorescence of PB was decreased in the presence of QHS, was studied. The steady-state catalytic rate depended upon enzyme and substrate concentrations, and the Michaelis-Menten parameters Km, Vmax and Kcat were 8.4×10?5 mol · L?1, 7.4×10?6 mol · L?1 s?1 and 50.23 s?1. The catalytic activity of enzyme was inhibited in the presence of deactivated agents and at high temperature, respectively. Under optimum conditions, linear relationship between fluo-rescence intensity change (F0?F) of pyronine B and concen-tration of QHS was in the range of 1.41×10?7―1.27×10?6 mol · L?1. The detection limit (3σ) was determined to be 2.7×10?8 mol · L?1. The proposed method was applied to the concentration determination of QHS in the media of plasma or urine samples.展开更多
Elevated level of hypochlorous acid(HClO)is closely associated with cancer development.Identifying HClO level in cancer cells would provide important evidence in either early-stage cancer diagnostics or monitoring of ...Elevated level of hypochlorous acid(HClO)is closely associated with cancer development.Identifying HClO level in cancer cells would provide important evidence in either early-stage cancer diagnostics or monitoring of its treatment efficiency.In this work,a new pyronine-based fluorescent probe for rapid and sensitive detection of HClO was developed by condensing meso-formyl pyronine(PyCHO)with 2-hydrazinopyridine to form meso-pyridylhydrazone-functionalized pyronine PyHP,PyHP is nonfluorescent due to the excited-state C=N isomerization nonradiative decay,whereas the HClO-triggered formation of meso-triazolopyridyl pyronine PyTP abolishes the C=N isomerization and thus greatly enhances the fluorescence.With the probe,the cancer cells/tumor were distinguished with high-contrast from normal ones by laser confocal fluorescence imaging,and the tumor-to-normal(T/N)ratios obtained exceed the clinically acceptable threshold of 2.0.Moreover,its capability of in vivo imaging tumor was also demonstrated.These results indicate the potential of PyHP as an effective tool in the early clinical diagnosis of cancers.展开更多
基金Supported by the National Natural Science Foundation of China(20075012) the Scientific Research Foundation of Hunan Educational Commit-tee (02C313)
文摘Fluorescence decrease ratio was applied to determine of arte misinin （qinghaosu, QHS） based on the catalytic effect of hemoglobin （Hb） using tetraethyldiaminoxanthenyl chloride （Pryonine B, PB） as monitor in this work, Experimental results show that the catalytic characteristics of Hb for QHS, being expressed as Michaelis-Menten parameters, Km, Vmax and Kcat are 2.8×10^-5 mol·L^-1, 4.2×10^-5 mol·L^-1·s^-1 and 280 s^-1 , respectively. Like hemin, enzymatic bioactivities of Hb is inhibited by both deactivated agents and high temperature whereas enhanced by ethanol. With the catalytic action of Hb, quantitative method of QHS can be established based on the fluorescence decrease of PB and linear relationship between the fluorescence decrease ratio F0/F and the concentration of QHS is in the range of （0.0-1.1）×10^-6 mol·L^-1 with detection limit （3σ） being 7. 2×10^-9 mol·L^-1, The concentration of QHS in the media of plasma or urine was detected using this method.
基金Project supported by the National Natural Science Foundation of China （No. 20075012） and the Natural Science Foundation of Hunan Educational Committee （No. 02C313）.
文摘Fluorescence decrease ratio （F0/F） was applied to determination of artemisinin （qinghaosu, QHS） based on the catalytic effect of tyrosinase using tetraethyldiaminoxanthenyl chloride （pyronine B, PB） as monitor. A catalyst used commonly in the decomposition of QHS, tyrosinase, exhibited higher binding activity than hemin, which was expressed as Michaelis-Menten parameters, km, Vmax, and kcat respectively. Interaction of QHS with tyrosinase was inhibited in the presence of deactivating agents at high temperature whereas enhanced by ethanol. Under optimal conditions, a concentration of 1.4×10^-7-8.4×10^-7 mol·L^-1of QHS could be determined on the basis of fluorescence decrease ratio of PB, with a detection limit 3tr of 2.6×10^-9 mol·L^-1. The proposed method was applied to detection of the concentration of QHS in the media of plasma and urine.
基金This work Was supported by the National Natural Science Foundation of China(Grant No.20075012)the Scientific Research Foundation of Hunan Educational Committee(Grant No.02C313).
文摘Enzyme-catalytic fluorescence determination of artemisinin (qinghaosu, QHS) was developed using pyronine B (PB) as substrate of horseradish peroxidase (HRP). The interaction between HRP and QHS was an enzyme-substrate model. The catalytic characteristic of HRP in the oxidation reaction, in which the fluorescence of PB was decreased in the presence of QHS, was studied. The steady-state catalytic rate depended upon enzyme and substrate concentrations, and the Michaelis-Menten parameters Km, Vmax and Kcat were 8.4×10?5 mol · L?1, 7.4×10?6 mol · L?1 s?1 and 50.23 s?1. The catalytic activity of enzyme was inhibited in the presence of deactivated agents and at high temperature, respectively. Under optimum conditions, linear relationship between fluo-rescence intensity change (F0?F) of pyronine B and concen-tration of QHS was in the range of 1.41×10?7―1.27×10?6 mol · L?1. The detection limit (3σ) was determined to be 2.7×10?8 mol · L?1. The proposed method was applied to the concentration determination of QHS in the media of plasma or urine samples.
基金Scientific and Technological Innovation Program of Colleges and Universities in Shanxi Province(Nos.2021L529,2021L530)the Fund for Shanxi“1331 Project”。
文摘Elevated level of hypochlorous acid(HClO)is closely associated with cancer development.Identifying HClO level in cancer cells would provide important evidence in either early-stage cancer diagnostics or monitoring of its treatment efficiency.In this work,a new pyronine-based fluorescent probe for rapid and sensitive detection of HClO was developed by condensing meso-formyl pyronine(PyCHO)with 2-hydrazinopyridine to form meso-pyridylhydrazone-functionalized pyronine PyHP,PyHP is nonfluorescent due to the excited-state C=N isomerization nonradiative decay,whereas the HClO-triggered formation of meso-triazolopyridyl pyronine PyTP abolishes the C=N isomerization and thus greatly enhances the fluorescence.With the probe,the cancer cells/tumor were distinguished with high-contrast from normal ones by laser confocal fluorescence imaging,and the tumor-to-normal(T/N)ratios obtained exceed the clinically acceptable threshold of 2.0.Moreover,its capability of in vivo imaging tumor was also demonstrated.These results indicate the potential of PyHP as an effective tool in the early clinical diagnosis of cancers.
