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
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
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
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.
