• 농약과학회지
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• 제8권3호
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• pp.162-167
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• 2004

십자화과 식물을 가해하는 세계적으로 중요한 해충의 하나인 배추좀나방(diamondback moth, Plutella xylostella)을 방제를 하기위하여 개발된 새로운 형태의 thiophosphoryl pyrazole계 살충제 KH502 유도체들의 구조와 살충활성을 CoMFA 방법으로 조사한 결과 효소의 결합부위에서 가장 중요한 역할을 하는 작용기는 trifluoro-methyl group과 thiophosphoryl group으로 밝혀졌다. 이와 같은 3D-QSAR 분석결과는 새로운 배추좀나방 방제용 살충제를 설계하는데 유용한 정보로 이용할 수 있을 것이다.

• 대한화장품학회지
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• 제39권4호
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• pp.329-335
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• 2013

본 연구에서는 기질 화합물로써 일련의 4-hydroxybenzyl alchol (4-HBA) 유도체들의 치환기($R_1$ 및 $R_2$) 변화에 따른 tyrosinase 활성저해에 관한 3차원적인 구조-활성 상관관계(3D-QSARs) 모델을 유도하고 정량적으로 검토하였다. 그 결과, 입체장(S), 정전기장(E), 소수성장(Hy), 수소결합 받게장(HA) 및 수소결합 주게장(HD)의 조합조건에서 통계적으로 양호한 CoMSIA FF 모델(상관성; $r^2$ = 0.858 및 예측성; $q^2$ = 0.951)을 유도하였다. 등고도 분석결과에 의하면 기질분자의 $R_2$-치환기는 입체적으로 작고 음전하를 띄며, 소수성이면서 수소결합 주게장을 선호하지 않는 치환기가 올수록 tyrosinase 활성저해 작용이 용이하다. 그리고 $R_1$-치환기는 수소결합 주게장을 선호하는 치환기 이어서 $R_1$-치환체가 용이하게 탈 양성자화가 일어나야 tyrosinase 활성저해 작용을 용이하게 할 것이라고 예상되며, 이를 위해서는 $R_1$-치환기가 비 치환체(H)이어야 될 것으로 예상되었다.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2761-2770
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• 2010

In this study, we have developed QSAR models for a series of 38 piperidine-4-carboxamide CCR5 antagonists using CoMFA, CoMSIA and HQSAR methods. Developed models showed good statistics in terms of $q^2$ and $r^2$ values. Best predictions obtained with standard CoMFA model ($r^2$ = 0.888, $q^2$ = 0.651) and combined CoMSIA model ($r^2$ = 0.892, $q^2$ = 0.665) with electrostatics and H-bond acceptor parameter. The validity of developed models was assessed by test set of 9 compounds, which showed good predictive correlation coefficient for CoMFA (0.804) and CoMSIA (0.844). Bootstrapped analysis showed statistically significant and robust CoMFA (0.968) and CoMSIA (0.936) models. Best HQSAR model was obtained with a $q^2$ of 0.662 and $r^2$ of 0.936 using atom, connection, hydrogen, donor and acceptor as parameters and fragment size (7-10) with optimum number of 6 components. Predictive power of developed HQSAR model was proved by test set and it was found to be 0.728.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1469-1473
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• 2010

Influences of alrylamino (R) substituents on the herbicidal activity ($pI_{50}$) of 1-(4-chloro-2-fluoro-5-propargyloxypheny)-3-(R)-thiourea analogues (1 ~ 35) against the barnyard grass (Echinochloa crusgalli) in the pre-emergence step were discussed quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) as the three dimensional quantitative structure-activity relationship (3D-QSAR) method. The statistically most satisfactory CoMFA models for the herbicidal activity against the barnyard grass had the better predictability ($r^2{_{cv.}}$) and correlativity ($r^2{_{ncv.}}$) than those of CoMSIA models. The optimized CoMFA model 1($r^2{_{cv.}}$ = 0.531 & $r^2{_{ncv.}}$ = 0.931) with the sensitivity to the perturbation (${d_q}^{2'}{dr^2}_{yy'}$ = 1.081) and the prediction ($q^2$ = 0.475) produced by a progressive scrambling analyses were not dependent on chance correlation. And statistical qualities with the atom based fit alignment (AF) were slightly higher than those of the field fit alignment (FF). According to the optimized CoMFA model 1, the contribution ratio (%) of the steric field (76.9%) on the herbicidal activity of the Thioureas was three-fold higher than that of the electrostatic field (20.1%) and the hydrophobic field (3.0%) had the least influence. A steric favor group is on the vicinity of the nitrogen atom in alrylamino (R) substituent, and a steric disfavor group is on the outer side of alrylamino (R) substituent. Thus, as the size of alrylamino (R) substituent increases, so does the herbicidal activity of the substituent.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1525-1530
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• 2004

Mutagen X (MX) exists in our drinking water as the bi-products of chlorine disinfection. Being one of the most potent mutagen, it attracted much attention from many researchers. MX and its analogs are synthesized and modeled by quantitative structure activity relationship (QSAR) methods. As a result, factors affecting this class of compounds have been found to be steric and electrostatic effects. We tried to collect all the data available from the literature. With both CoMFA and CoMSIA various combinations of physiochemical parameters were systematically studied to produce reasonable 3-dimensional models. The best model for CoMFA gave $q^2$ = 0.90 and $r^2$ = 0.97, while for CoMSIA $q^2$ = 0.85 and $r^2$ = 0.94. So the models seem to be reasonable. Unlike previous result of CoMFA, in our case steric parameter alone gave the best statistics. Although the steric contribution was found to be the most important in both CoMFA and CoMSIA, steric parameter along with electrostatic parameter produced slightly better model in CoMSIA. Overall, steric contribution is clearly the most important single factor. However, when we compare chlorine and bromine substitution, chlorine substitution can be more mutagenic. This indicates that other factors such as electrostatic effect also influence the mutagenicity. From the contour maps, steric contribution seems to be focused on rather small area near C6 substituent of the furanone ring, rather than C3 substituent. Therefore the locality of steric contribution can play a significant role in mutagenicity.

• Archives of Pharmacal Research
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• 제9권2호
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• pp.99-110
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• 1986

In order to use for metabolic studies of tranylcypromine (TCP), TCP-phenyl-$d_{5}$ was synthesized via the intermediates, 3-benzoylpropionic acid-$d_{5}$ and trans-2-phenylcyclopropanecarboxylic acid-$d_{5}$ -TCP(0.22 mmole/kg) and its deuterated analog were administered s. c. to the rats and GC/MS analyses of the urines led to the detection of N-acetyltranylcypromine (ATCP) and glucuronide conjugate of phenyl-hydroxylated ATCP. MAO activities in rat brain were measured using serotonin as the substrate. In vitro $IC_{50}$ of ATCP was determined to be $10^{-3}M$. The inhibitions by ATCP were not dependent on the preincubation time and were reversed by washing sedimented mitochondrial pellets after the preincubation. In vivo MAO inhibitions at various times of 0.5, 1.5, 3, 6, 12, and 23 hr after the administration of 0.4 mmole/kg (i. p. ) of ATCP were found to be 0.13, 73, 90, 89, and 74 %, respectively. Similarly, the inhibition percents by 0.015 mmole/kg (i. p. ) of TCP were 94, 99, 95, 91, 71 and 49%. The results strongly suggest that deacetylated product of ATCP may account for its in vivo MAO inhibition. The relationship between the metabolism via phenyl-hydroxylation and the in vivo potency of TCP was examined by QSAR study and it was found that groupings discriminating between the compounds with p-substituents and those without them only ensure high correlations, suggesting that ring-hydroxylation which occurs at the para position in most of the compounds is a determining factor to the potency of TCP.

• 통합자연과학논문집
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• 제7권3호
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• pp.166-172
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• 2014

Caspases, a family of cysteinyl aspartate-specific proteases plays a central role in the regulation and the execution of apoptotic cell death. Activation of caspases-3 stimulates a signaling pathway that ultimately leads to the death of the cell. Hence, caspase-3 has been proven to be an effective target for reducing the amount of cellular and tissue damage. In this work, comparative molecular field analysis (CoMFA) was performed on a series of 3, 4-dihydropyrimidoindolones derivatives which are inhibitors of caspase-3. The best predictions were obtained for CoMFA model ($q^2=0.676$, $r^2=0.990$). The predictive ability of test set ($r^2_{pred}$) was 0.688. Statistical parameters from the generated QSAR models indicated the data is well fitted and have high predictive ability. Our theoretical results could be useful to design novel and more potent caspase-3 derivatives.

• 통합자연과학논문집
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• 제9권2호
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• pp.121-127
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• 2016

CXC chemokine receptor 2 (CXCR2) is a prominent chemokine receptor on neutrophils. The neutrophilic inflammation in the lung diseases is found to be largely regulated through CXCR2 receptor. Antagonist of CXCR2 may reduce the neutrophil chemotaxis and alter the inflammatory response. Hence, in the present study, ligand based Comparative molecular field analysis (CoMFA) was performed on a series of CXCR2 antagonist named pyrimidine-5-carbonitrile-6-alkyl derivatives. The optimum CoMFA model was obtained with statistically significant cross-validated coefficients ($q^2$) of 0.568 and conventional coefficients ($r^2$) of 0.975. The contour maps suggest the important structural modifications and this study can be used to guide the development of potent CXCR2 antagonist.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1237-1240
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• 2011

In this study, we have developed a ligand-based in-silico prediction model to classify chemical structures into hERG blockers using Bayesian and random forest modeling methods. These models were built based on patch clamp experimental results. The findings presented in this work indicate that Laplacian-modified naive Bayesian classification with diverse selection is useful for predicting hERG inhibitors when a large data set is not obtained.

• 통합자연과학논문집
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• 제3권3호
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• pp.162-167
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• 2010

A pseudoreceptor combines structure-based and ligand-based techniques to represent a unifying concept for both receptor mapping and ligand matching. In this molecular modeling approach, there are opportunities to construct the pseudoreceptor models using a set of small molecules. To build a reliable pseudoreceptor model, we need a set of ligand molecules with known affinity (biological activity) to generate 3D bioactive conformation for each of these ligand molecules. Several software packages are available to generate a pseudoreceptor model and this can provide an entry point for structure based drug discovery in cases where receptor structure information is not available. In this review, we presented the concept of pseudoreceptor, as well as discussed about various software packages available to generate a pseudoreceptor model.