Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination proc- esses. To mitigate scales, organic anti-scalants are often used. If the dosages of anti-scalants are reduced, by using...Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination proc- esses. To mitigate scales, organic anti-scalants are often used. If the dosages of anti-scalants are reduced, by using other much cheaper scale inhibitors, RO running cost will decrease greatly. The present paper investigated the inhi- bition of CaCO3 precipitation by zinc ions in RO system. The results show that the zinc ion concentration of 2mg?L-1 was able to exert a marked suppression effect on both bulk precipitation of CaCO3 and on membrane scaling on waters of moderate hardness.展开更多
TM208 and TM209,dithiocarbamate derivatives with potential anti-cancer effects,were evaluated in reversible and time-dependent cytochrome P450(CYP)3A inhibition assays in rat liver microsomes using testosterone as pro...TM208 and TM209,dithiocarbamate derivatives with potential anti-cancer effects,were evaluated in reversible and time-dependent cytochrome P450(CYP)3A inhibition assays in rat liver microsomes using testosterone as probe substrate.Both compounds were found to be weak reversible inhibitors and moderate mechanism-based inhibitors of rat CYP3A.For reversible inhibition on rat CYP3A,the Ki values of competitive inhibition model were 12.10±1.75 and 13.94±1.31 μM,respectively.For time-dependent inhibition,the inactivation constants(K_(l))were 31.93±12.64 and 32.91±15.58 μM,respectively,and the maximum inactivation rates(kinact)were 0.0349770.0069 and 0.0725970.0172 min^(-1) respectively.These findings would provide useful in vitro information for future in vivo DDI studies on TM208 or TM209。展开更多
A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolys...A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.展开更多
Influence of fullerene (C60) derivatives on M-MuLV reverse transcriptase activity is investi- gated. Two water-soluble fullerene derivatives, fullerol (C60(OH)23-24) and trimalonic acid C60 (TMA C60, C63(COOH)6) are u...Influence of fullerene (C60) derivatives on M-MuLV reverse transcriptase activity is investi- gated. Two water-soluble fullerene derivatives, fullerol (C60(OH)23-24) and trimalonic acid C60 (TMA C60, C63(COOH)6) are used in the experiments and their effects on in vitro reverse transcription-polymerase chain reaction (RT-PCR) of β-actin mRNA in HeLa cells are determined. PCR products are detected by agarose gel electrophoresis. It is found that the amounts of PCR products decrease with addition of either of two fullerene derivatives to RT reaction mixture. The inhibition of fullerene derivatives is dose-dependent, and IC50 values of fullerol and TMA C60 are 0.089 and 0.039 mmol/L, respectively. The amount of PCR products obtained by direct addition of fullerol or TMA C60 to PCR are greater than those obtained by addition of the equivalent amount of fullerol or TMA C60 to RT, indicating an inhibitory ef- fect of fullerol or TMA C60 on RT. The compensative experiment of M-MuLV reverse transcriptase shows that increasing enzyme amounts can antagonize the activity of fullerol or TMA C60. These results imply that fullerenes can inhibit M-MuLV reverse transcriptase activity, with the inhibition of TMA C60 slightly stronger than fullerol, and that their potential in treatment of diseases induced by RNA viruses such as leukemia virus needs further investigation.展开更多
基金Supported by the National Natural Science Foundation of China (No.20306015) and the Scientific Research Foundation of theState Education Ministry for Returned Overseas Chinese Scholars (No.[2003]406).
文摘Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination proc- esses. To mitigate scales, organic anti-scalants are often used. If the dosages of anti-scalants are reduced, by using other much cheaper scale inhibitors, RO running cost will decrease greatly. The present paper investigated the inhi- bition of CaCO3 precipitation by zinc ions in RO system. The results show that the zinc ion concentration of 2mg?L-1 was able to exert a marked suppression effect on both bulk precipitation of CaCO3 and on membrane scaling on waters of moderate hardness.
基金supported by the funds of Peking University Comprehensive Center of Drug Discovery and Development(2009ZX09301-010)from China Ministry of Science and Technology。
文摘TM208 and TM209,dithiocarbamate derivatives with potential anti-cancer effects,were evaluated in reversible and time-dependent cytochrome P450(CYP)3A inhibition assays in rat liver microsomes using testosterone as probe substrate.Both compounds were found to be weak reversible inhibitors and moderate mechanism-based inhibitors of rat CYP3A.For reversible inhibition on rat CYP3A,the Ki values of competitive inhibition model were 12.10±1.75 and 13.94±1.31 μM,respectively.For time-dependent inhibition,the inactivation constants(K_(l))were 31.93±12.64 and 32.91±15.58 μM,respectively,and the maximum inactivation rates(kinact)were 0.0349770.0069 and 0.0725970.0172 min^(-1) respectively.These findings would provide useful in vitro information for future in vivo DDI studies on TM208 or TM209。
基金Project supported by the National Natural Science Foundation of China (No. 30070200) and the Major Project of Hubei Province Department of Education China (No. 2003A009).
文摘A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.
文摘Influence of fullerene (C60) derivatives on M-MuLV reverse transcriptase activity is investi- gated. Two water-soluble fullerene derivatives, fullerol (C60(OH)23-24) and trimalonic acid C60 (TMA C60, C63(COOH)6) are used in the experiments and their effects on in vitro reverse transcription-polymerase chain reaction (RT-PCR) of β-actin mRNA in HeLa cells are determined. PCR products are detected by agarose gel electrophoresis. It is found that the amounts of PCR products decrease with addition of either of two fullerene derivatives to RT reaction mixture. The inhibition of fullerene derivatives is dose-dependent, and IC50 values of fullerol and TMA C60 are 0.089 and 0.039 mmol/L, respectively. The amount of PCR products obtained by direct addition of fullerol or TMA C60 to PCR are greater than those obtained by addition of the equivalent amount of fullerol or TMA C60 to RT, indicating an inhibitory ef- fect of fullerol or TMA C60 on RT. The compensative experiment of M-MuLV reverse transcriptase shows that increasing enzyme amounts can antagonize the activity of fullerol or TMA C60. These results imply that fullerenes can inhibit M-MuLV reverse transcriptase activity, with the inhibition of TMA C60 slightly stronger than fullerol, and that their potential in treatment of diseases induced by RNA viruses such as leukemia virus needs further investigation.
基金supported by the National Natural Science Foundation of China(50773009)Science and Technology Commission of Shanghai Municipality,China(08JC1400600)~~
