• Reproductive and Developmental Biology
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• 제29권1호
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• pp.43-48
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• 2005

돼지 웅성 페르몬인 5a-androst-16-en-3-one을 대체할 수 있는 활성 분자를 탐색하여 가축의 생산과 수요를 조절하기 위한 생물학적 자극 통제 수단으로 활용하고자 냄새 분자로서 2-cyclohexyloxytetrahydrofurane (A) 및 2-phenoxytetrahydrofurane (B) 유도체들의 구조 변화와 수용체인 porcine odorant binding protein (pOBP)에 대한 결합친화력 상수(p[Od.]/sub 50/) 사이의 정량적인 구조-활성관계에 관한 분자 HQSAR 모델XI을 유도하였다. 냄새 분자 중에서 cyclohexyl-치환체(A)가 phenyl-치환체(B)보다 높은 결합 친화력을 나타내었으며(A>B) 모델XI은 분자 조각크기(5∼8), 홀로그램 길이(97 bin)의 키랄성(chirality)조건에서 예측성(q²=0.916)과 상관성(r²=0.988)이 매우 양호하였다. 기여도(contribution map)로부터 냄새 분자의 결합 친화력 상수에 기여하는 부분은 2-oxyfuryl group의 C3 및 C5 원자인 반면에 cyclohexyl 고리상 tert-butyl group의 중심 탄소 원자와 furyl group의 C4 원자 부분은 기여하지 않았다.

• Archives of Pharmacal Research
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• 제16권4호
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• pp.289-294
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• 1993

A binding protein of radio-labeled sanjoinine-A (fangufoline) in rat brain cytoplasm was investigated, using an equilibrium dialysis technique. The labeled agent was bound to the cytosol fraction with two distinctly different types of sets in calclum ion-dependent manner. The bound protein was identified as calmodulin by dgel filtration of the sanjoinine-A bound cytosol fraction on a Sephadex G-75 column. Calmodulin was bound to sanjoinine-A bound at two sets of binding sites in the calculated as two at high affinity sites $(Kd=1.1\;mu{M)}$ and four at low affinity sites $(Kd=3.1\;\mu{M)}$.

• Journal of Pharmaceutical Investigation
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• 제23권3호
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• pp.119-125
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• 1993

The protein binding of salicylate analogs has been investigated by equilibrium dialysis. A series of binding experiments were performed in order to elucidate the effects of physicochemical properties of salicylate analogs on the binding with bovine serum albumin. Attempts to correlate affinity constants with capacity factor, steric factor and Hammett ${\sigma}$ values suggested hydrophobic forces to be involved in the binding of salicylate analogs. Steric factor contributes to binding process partly, whereas electronic interaction appears to be insignificant.

• 약학회지
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• 제39권6호
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• pp.645-653
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• 1995

Dibenamine inhibited [$^{3}$H]quinuclidinyl benzilate ([$^{3}$H]QNB) binding in both concentration and incubation time-dependent manners. The $IC_{50}$/ value of dibenamine for the inhibition of the specific binding of 100 pM [$^{3}$'H]QNB following incubation of cerebral microsomes with dibenamine at 37.deg. C for 15 min was 20.mu.M. Dibenamine irreversibly decreased the binding site concentration for [$^{3}$H]QNB binding without affecting the affinity of [$^{3}$H]QNB for the muscarinic receptor. Analysis of the pirenzepine inhibition curve of [$^{3}$H]QNB binding to cerebral microsomes indicated the presence of two receptor subtypes with high(M$_{1}$ receptor, Ki=5nM) and low (M$_{2}$ receptor, Ki=160nM) affinity for pirenzepine. However, dibenamine(20.mu.M) treatment under the condition employed in these experiments caused steepening of the pirenzepine competition curve. The Ki value for pirenzepine in dibenamine treated-microsomes was approximately 120nM. suggesting a selective decrease in the number of M$_{1}$ receptor. Although dibenamine also inhibited [$^{3}$H]QNB binding to ventricular microsomes with $IC_{50}$/ value of 120.mu.M, the sensitivity for dibenamine in the ventricle was much lower than that in the cerebrum. These results indicate that dibenamine at low concentrations welectively inactivates the muscarinic M$_{1}$ receptor.

• Biomolecules & Therapeutics
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• 제2권4호
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• pp.361-368
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• 1994

The nature of the muscarinic receptors in bovine adrenal medulla was investigated in this study. [$^3$H]Quinuclidinyl benzilate(QNB) specifically bound to a single class of muscarinic receptor with a $K_{D}$ value of about 70 pM in bovine adrenal medullary, cardiac ventricular and ileal homogenates. Pirenzepine inhibition curves of [$^3$H]QNB binding to cardiac ventricular and ileal homogenates were steep, indicating the presence of a single class of binding site for pirenzepine with a Ki value of 990 nM and 508 nM, respectively. However, pirenzepine/[$^3$H]QNB competition binding curves in adrenal medulla suggested the presence of two binding sites (Hill coefficient=0.59) with a high( $M_1$) and a low( $M_2$) affinity. Respective Ki values for pirenfepine were 16 nM and 633 nM, with 44% of total sites having a high affinity( $M_1$). Gallamine, which is selective to cardiac $M_2$-receptor, inhibited [$^3$H]QNB binding to adrenal medullary, cardiac ventricular and ileal homogenates with Ki values of 12 $\mu$M, 6 $\mu$M and 13 $\mu$M, respectively. Thus, the binding affinities of pirenzepine and gallamine for $M_2$-receptor in adrenal medulla were similar to those in ileum, which contains the $M_3$-receptor. These results indicate that the $M_1$- and $M_3$- muscarinic receptor subtypes coexist in the bovine adrenal medulla.a.

• 대한약리학회지
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• 제19권2호
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• pp.57-67
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• 1983

Guinea-Pig의 myenteric plexus-longitudinal muscle preparation에서 morphine과 naloxone 효과(效果)에 미치는 전해질(電解質)의 영향(影響)을 관찰(觀察)하였다. 표본(標本)은 Krebs-Henseleit bicarbonate tufter solution 으로 채운 organ bath에 현수(懸垂)하고 0.2Hz로 전기자극(電氣刺戟)하였다. Morphine은 전기자극(電氣刺戟)에 의(依)한 근편수축(筋片收縮)을 억제(抑制)하였으며, 이때 $ID_{30}$은 약(約) 190nM이었다. 이와같은 morphine의 억제작용(抑制作用)은 bath내(內) $Na^+$ 또는 $K+$ 농도(濃度)를 감소(減少)시키거나 $Mg^{2+}$을 가(加)하면 강화(强化)되었으며, $Ca^{2+}$ 농도(濃度)를 증가(增加)시키거나 $Mg^{2+}$를 농도(濃度)를 감소(減少)시키면 약화(弱化)되었다. Naloxone은 morphine의 작용(作用)을 억제(抑制)하였으며, 이때 naloxone에 대(對)한 affinity index인 $pA_2$ value는 약(約) 8.8이었고 that내(內) 전해질(電解質) 농도(濃度)를 변동(變動)시켜도 영향(影響)받지 않았다. 이 성적(成積)은 전해질(電解質) 변동(變動)으로 인(因)한 morphine의 작용변동(作用變動)은 전해질(電解質)이 opiate receptor의 affinity를 변동(變動)시킨다는 opiate-receptor binding실험(實驗)에서와는 달리 전해질(電解質) 변동(變動)에 의(依)한 functional opiate receptor의 affinity 변동(變動)에 의(依)한 것이 아님을 시사(示唆)한다.

• 대한수의학회지
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• 제44권2호
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• pp.233-239
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• 2004

This study was designed to quantitative assay of cellular receptor globotriosyl ceramide($Gb_3$) and globotetraosyl ceramide($Gb_4$) and to determine binding affinity of the receptors for Shigatoxin 2e in difference with day olds of pig. The amount of $Gb_3$ and $Gb_4$ extracted from each swine tissue were detected in order of spleen, ileocecum, kidney, and jejunum. The amount of $Gb_3$ and $Gb_4$ extracted from each swine ileocecum and jejunum in different day old swine were detected in order of 24, 6, 98, 12 and 35, but the difference of amount was not significant. The binding affinity of $Gb_4$ extracted from ileocecum and jejunum with different day old swine for Stx2e were shown that the extracts of 24, 12, and 35 days old swine were higher significantly than that of 6 and 98 days old swine.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.758-762
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• 2007

A new alkyldithiocarbonate (xanthate), as sodium salts, C2H5OCS2Na, was synthesized by the reaction between CS2 with ethyl alcohol in the presence of NaOH. The new xanthate was characterized by 1H NMR, IR and elemental analysis. Then, the new synthesized compound was examined for functional study of cresolase activity of Mushroom Tyrosinase (MT) from a commercial source of Agricus bisporus in 10 mM phosphate buffer pH 6.8, at three temperatures of 10, 20 and 33℃ using UV spectrophotemetry. 4-[(4-methylphenyl)- azo]-phenol (MePAPh) was used as a synthetic substrate for the enzyme for cresolase reaction. The results show that ethyl xanthate can activate or inhibit the cresolase activity of mushroom tyrosinase depending to the concentration of ethyl xanthate. It was concluded that the enzyme has two distinct sites for ethyl xanthate. The first one is a high-affinity activation site and the other is a low-affinity inhibition site. Activation of the enzyme in the low concentration of ethyl xanthate arises from increasing the affinity of binding for the substrate as well as increasing the enzyme catalytic constant. The affinity of ligand binding in the activation site is decreased by increasing of the temperature, which is the opposite result for the inhibition site. Hence, the nature of the interaction of ethyl xanthate is different in two distinct sites. The binding process for cresolase inhibition is only entropy driven, meanwhile the binding process for cresolase activation is not only entropy driven but also enthalpy driven means that hydrophobic interaction is more important in the inhibition site.

• 약학회지
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• 제34권4호
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• pp.224-237
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• 1990

A single uniform population of specific, saturable, high affinity binding site of $[^3H]QNB$ guinuclidinyl benzilate(QNB) was identified in the rat cerebral microsomes. The Kd value(37.2 pM) for $[^3H]QNB$ calculated from the kinetically derived rate constants was in agreement with the Kd value(48.9 pM) determined by analysis of saturation isotherms at various receptor concentrations. Dimenhydrinate(DMH), histamine $H_1-blocker$, increased Kd value for $[^3H]QNB$ QNB without affecting the binding site concentrations and this effect resulted from the ability of DMH to slow $[^3H]QNB-receptor$ association. Pirenzepine inhibition curve of $[^3H]QNB$ binding was shallow(nH = 0.52) indicating the presence of two receptor subtypes with high ($M_1-site$) and low($M_2-site$) affinity for pirenzepine. Analysis of these inhibition curves yielded that 68% of the total receptor populations were of the $M_1-subtype$ and the remaining 32% of the $M_2-subtype$. Ki values for the $M_1-$ and $M_2-subtypes$ were 2.42 nM and 629.3 nM, respectively. Ki values for $H_1-blockers$ that inhibited $[^3H]QNB$ binding varied with a wide range ($0.02-2.5\;{\mu}M$). The Pseudo-Hill coefficients for inhibition of $[^3H]QNB$ binding by most of $H_1-blockers$ examined except for oxomemazine inhibition of $[^3H]QNB$ binding were close to one. The inhibition curve for oxomemazine in competition with $[^3H]QNB$ was shallow(nH = 0.74) indicating the presence of two receptor populations with different affinities for this drug. The proportion of high and low affinity was 33:67. The Ki values for oxomemazine were $0.045{\pm}0.016\;{\mu}M$ for high affinity and $1.145{\pm}0.232\;{\mu}M$ for low affinity sites. These data indicate that muscarinic receptor blocking potency of $H_1-blockers$ varies widely between different drugs and that most of $H_1-blockers$ examined are nonselective antagonist for the muscarinic receptor subtypes, whereas oxomemazine might be capable of distinguishing between subclasses of muscarinic receptor.

• BMB Reports
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• 제42권3호
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• pp.166-171
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• 2009

Hsp70s assist in the process of protein folding through nucleotide-controlled cycles of substrate binding and release by alternating from an ATP-bound state in which the affinity for substrate is low to an ADP-bound state in which the affinity for substrate is high. It has been long recognized that the two-domain structure of Hsp70 is critical for these regulated interactions. Therefore, it is important to obtain information about conformational changes in the relative positions of Hsp70 domains caused by nucleotide binding. In this study, analytical ultracentrifugation and dynamic light scattering were used to evaluate the effect of ADP and ATP binding on the conformation of the human stress-induced Hsp70.1 protein. The results of these experiments showed that ATP had a larger effect on the conformation of Hsp70 than ADP. In agreement with previous biochemical experiments, our results suggest that conformational changes caused by nucleotide binding are a consequence of the movement in position of both nucleotide- and substrate-binding domains.