• BMB Reports
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• v.29 no.3
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• pp.225-229
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• 1996

Effects on thrombin by an amphipathic cation, dequalinium, which has been recognized as an anticarcinoma agent were investigated with small chromogenic substrates such as Na-benzoyl-DL-argininep-nitroanilide (BApNA), H-D-phenylalanyl-L-pipecoyl-L-arginine-p-nitroanilide (S-2238), and Na-p-tosyl-L-arginine methyl ester (TAME). Among them, only TAME hydrolysis due to an esterase activity of the enzyme was significantly activated to 81% at 20 ${\mu}M$ dequalinium in the absence of NaCl. This stimulation became even higher in the presence of 0.2 M NaCl to 3.5-fold at 60 ${\mu}M$ dequalinium. This specific activation of thrombin was well correlated with the results of in vitro coagulation tests measuring the activated partial thromboplastin time (APTT) and the prothrombin time (PT) It is pertinent. therefore, to suggest that the esterase activity should be examined in addition to the effects on 5-2238 hydrolysis when especially any regulators not directed to an active site of thrombin need to be studied. We also expect that dequalinium could be a useful tool for studying structure-function relationship of thrombin and blood coagulation.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.274-280
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• 2009

In order to elucidate the adsorption mechanism of the herbicide, bentazon and its metabolites on soil, their adsorption patterns on soil and six adsorbents were investigated with Freundlich, Langmuir and linear isotherm. Freundlich constants ($K_f$) and maximum adsorption amount($Q^0$) of bentazon on soil was 0.55 and 3.97. Kd and Koc values of it were 0.18 and 18. The all of metabolites used except deisopropylbentazon amounts sorbed on the soil were much higher than bentazon. The most of 8-hydroxybentazon was adsorbed on soil showing $K_f$ = 316.6, $Q^0$ = 3,488, Kd = 29.7 and Koc = 2,970. Bentazon, deisopropylbentazon and 8-hydroxybentazon were shown high affinity to anion exchange regardless of pH and $NH_2$ in low pH range. Reversed phase $C_{18}$ resulted in 100% retention of N-methylbentazon regardless of pH and other metabolites were retained below 40%. The AIBA was strongly adsorbed in silica gel, COOH and cation exchange phase but poor retention was on anion exchange sorbent. 2-Aminobenzoic acid showed an amphipathic nature which had high affinity for COOH and cation exchange phase at pH 7.0 as well as $NH_2$ and anion exchange sorbent at pH 3.0.