• 대한화학회지
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• 제28권3호
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• pp.185-193
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• 1984

송아지 胸線 DNA의 nucleotide 당 spermine 0.016 분자의 비율로 結合되는 spermine 濃度에서 그 DNA와 ethidium과의 結合에 對한 Hill 係數는 1.7인 反面에 spermine이 存在하지 않는 條件에서는 그 Hill 係數가 0.38이었다. Spermine에 依한 DNA의 viscometric titration data, 260nm에서의 anomalous absorbance-temperature profile 및 粘性度-溫度 樣相과 더불어 이 data를 基礎로 하여 spermine 結合에 依하여 誘發되는 conformational transition의 allosteric propagation이 DNA의 凝縮된 構造로의 單分子的 collapse에 관여됨을 豫測할 수 있다.

• 약학회지
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• 제25권4호
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• pp.161-165
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• 1981

The binding of two cephalosporins, cephalothin and cefazoline to human serum albumin(HSA) was studied by difference spectrophotometry using a spectrophotometric probe, 2-(4'-hydroxybenzeneazo) benzoic acid. The probe is strong visible absorbing material which interacts with serum albumin to give characteristic spectrophotometric peaks and provides the basis for a convenient assay to measure free and bound amounts in the presence of serum albumin and competitive drugs. The results obtained showed that the probe and cephalosporin compete for the same binding site on human serum albumin; thus the probe can be used to gauge the displacement of cephalosporins from human serum albumin. The data were interpreted on the basis of theory of multiple equilibria. The number of binding sites of human serum albumin for 2-(4'-hydroxybenzeneazo) benzoic acid(HBAB), cephalothin and cefazoline appears to be 4. By using this technique the binding constants were found as follows: HSA-HBAB, $7.89{\times}10^{4}M^{-1}$; HSA-cephalothin, $1.09{\times}10^{3}M^{-1}$ ; HSA-cefazoline, $1.21{\times}10^{3}M^{-1}$.

• 한국가축번식학회지
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• 제18권2호
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• pp.95-99
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• 1994

우수성이 이미 입증된 oxytocin antagonist-I(AI)이 발정된 쥐의 자궁내 옥시토신 수용체 수와 결합친화력이 어떤 영향을 미치는 지를 알아보는 것이 본 연구의 목적이었다. 마취된 흰쥐들에게 5$\mu\textrm{g}$의 AI를 투여하였으며, 30분과 4시간후에 도살하였다. 자궁조직을 회수하여 잘게 잘라 냉동시킨 다음 다시 자궁조직을 분쇄한 후 단계적인 초고속 원심분리를 거쳐 옥시토신 수용체가 있는 세포막을 추출하였다. 옥시토신 수용체 분석은 높은 활동성을 보이는 옥시토신 길항제와 방사선 동위원소가 붙지 않은 옥시토신이 경쟁하는 포화상태에서 실시하였다. 옥시토신 수용체의 수와 결합친화력은 nonlinear curve fitting 방법에 의해 계산되었다. 연구 결과, AI이 투여된 흰쥐들은 수용체의 수와 결합력에 있어서 control과 유의한 차이를 보이지 않았다(p>0.05). 결론적으로 AI은 옥시토신 수용체의 수와 결합친화력을 변화시키지 않고 다만 옥시토신과 경쟁력으로 억제하는 작용을 옥시토신 수용체에서 나타낸다는 것을 이 연구에서 입증하였다.

• Molecules and Cells
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• 제43권7호
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• pp.607-618
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• 2020

microRNAs (miRNAs) are non-coding RNA molecules involved in the regulation of gene expression. miRNAs inhibit gene expression by binding to the 3' untranslated region (UTR) of their target gene. miRNAs can originate from transposable elements (TEs), which comprise approximately half of the eukaryotic genome and one type of TE, called the long terminal repeat (LTR) is found in class of retrotransposons. Amongst the miRNAs derived from LTR, hsa-miR-3681 was chosen and analyzed using bioinformatics tools and experimental analysis. Studies on hsa-miR-3681 have been scarce and this study provides the relative expression analysis of hsa-miR-3681-5p from humans, chimpanzees, crab-eating monkeys, and mice. Luciferase assay for hsa-miR-3681-5p and its target gene SHISA7 supports our hypothesis that the number of miRNA binding sites affects target gene expression. Especially, the variable number tandem repeat (VNTR) and hsa-miR-3681-5p share the binding sites in the 3' UTR of SHISA7, which leads the enhancer function of hsamiR-3681-5p to inhibit the activity of VNTR. In conclusion, hsa-miR-3681-5p acts as a super-enhancer and the enhancer function of hsa-miR-3681-5p acts as a repressor of VNTR activity in the 3' UTR of SHISA7.

• 대한약리학회지
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• 제20권2호
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• pp.23-34
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• 1984

실험적으로 명암주기 또는 암주기에 적응시킨 백서의 간뇌 homogenate에서 opiate receptor의 일중변동 유무를 검토하고, circadian rhythm에 영향을 미치는 것으로 알려진 수종 중추작용약물의 영향을 보고 저 7 group에서 4시간 간격으로 1일 6회 maximum $^3H-morphine$ binding을 측정하여 다음과 같은 성적을 얻었다. 1) L : D, 12 : 12에 적응시킨 대조군에서 maximum $^3H-morphine$ binding은 22시에 최고에 달하는 매우 유의한 일중변동을 보였고, 24시간 평균 $^3H-morphine$ binding치는 $0.45{\pm}0.03\;pmole/mg Protein이었다. 2) 지속적인 암적응을 시킨 D : D, 12 :12군에서 $^3H-morphine$ binding의 일중변동은 14시에 최하, 그리고 2시에 최고의 binding치를 보이는 만상성의 일주변동은 보였으며 대조군의 곡선과는 그 shape, Phase, 진폭, 최고 또는 최하 binding시기 및 24시간평균 opiate수용체의 수에 현저한 차이가 있었다. 3) 지속적인 암적응, reserpine, pargyline, imipramine, amphetamine 또는 chlorpromazine 처리는 opiate receptor의 일중변동을 변화시켰다. 4) 그러나 전 실험군에서 Kd치는 변동되지 않았다. 이상 실험성적으로 백서뇌내 opiate수용체의 일중변동은 수용체의 질적변동이 아닌 수적인변동에 의하고, 지속적인 암적응이나 circadian rhythm을 변동시키는 중추성 약물들이 opiate receptor의 일중변동을 변화시킬 수 있으며, 또한 동통을 포함하여 제종 진통제의 효과가 일중변동을 일으키는 것은 opiate receptor의 일중변동과 일정한 관계가 있을 것으로 추측하였다.

• BMB Reports
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• 제36권2호
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• pp.149-153
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• 2003

The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.

• Archives of Pharmacal Research
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• 제16권4호
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• pp.305-311
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• 1993

$Na^+,K^+$-ATPase activity, $Na^+$-dependent phosphorylation, and $[^3H]$ ouabain binding in sarcolemma prepared from 4 week old spontaneously hypertensive rat(SHR) ventricles were compared to the same parameters in sarcolemma from age matched nomotensive Wister-Kyoto (WKY) rat ventricles to examine whether the reduced myocardial $Na^+$-pump activity in SHR is an inherited enzymatic defect or a second phenomenon due to sustained hypertension. The total body weights, ventricular weights, and blood pressures were the same for SHR and WKY. No significant differences in sarcolemmal protein content and protein recovery were noted between the two groups. Sarcolemma isolated from SHR ventricles showed significantly less $Na^+,K^+$-ATPase activity ande number of phosphorylation sites when compared to sarcolemma from the WKY ventricles. Equilibrium binding of $[^3H]$ouabain and the tumover number of myocardial $Na^+,K^+$-ATPase, however, were the same for both groups. These reults indicate that the low affinity $(\alpha,\;or\;\alpha^1)\;\alpha$ isoform is the same in ventricles of SHR and WKY. The reduced amount of isoform of the $Na^+,K^+$-ATPase inprehypetensive SHR ventricles may play some role in the development of hypertension.

• 생명과학회지
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• 제4권3호
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• pp.92-101
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• 1994

With the rapid development of bioorganic chemistry recently, a field of artificial enzymes has a great concern from the industrial point of view. A number of possibilities now exist ofr the construction of artificial enzymes. They must posses two structural entities, a substrate-binding site and a catalytically effective site. It has been found that producing the facility for substrate binding is relatively straightforward but catalytic sites are somewhat more difficult. Therefore, synthetic catalysts do not yet match all the properties of an enzyme, however, the design of catalysts has lead to very powerful effects. This article reviews the existing literature on the modeling of artificial enzymes using cyclodextrin, modified cyclodextrin and crown compounds.

• 한국정보과학회논문지:시스템및이론
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• 제29권9호
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• pp.493-502
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• 2002

다중 컴퓨터 네트워크의 고장 감내에 대한 대표적인 결정적 척도로 연결도와 에지 연결도가 있다. 연결도나 에지 연결도는 어떤 정점 분리 집합이나 에지 분리 집합을 제거했을 때 남은 그래프의 형태를 고려하지 않는다는 문제가 있다. 이러한 단점을 보완하기 위해서 superconnectivity, toughness, scattering number, vertex-integrity, binding number, restricted connectivity와 같은 일반화된 연결성 척도들이 함께 사용된다. 이 논문에서는 재귀원형군과 하이퍼큐브의 고장 감내에 대한 이러한 결정적 척도를 분석하고, 고장 감내 측면에서 비교한다.

• 약학회지
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• 제30권1호
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• pp.42-46
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• 1986

The binding characteristics of five cephalosporins, cefamandole, ceftriaxone, cefoxitin, latamoxef, and cefotetan to bovine serum albumin (BSA) was examined by UV difference spectrophotometry. 2-(4'-hydroxybenzeneazo) benzoic acid was used as the spectrophotometric probe. Competitive bindings between the probe and cephalosporins were observed. Based on the Scatchard plot, the BSA appeared to have two classes of binding sites in BSA binding with cephalosporins. The number of primary binding sites appears to be one, secondary binding sites appears to be three. The binding constants were found as follows: BSA-HBAB; $K_1^{obs}$=8.39$\times$$10^4$ $M^{-1}$, $K_2^{obs}$=1.60$\times$$10^4$ $M^{-1}$, BSA-Cefamandole; $K_1^{obs}$=5.44$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=0.74$\times$$10^3$ $M^{-1}$, BSA-Cefotriaxone; $K_1^{obs}$=6.78$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=0.88$\times$$10^3$ $M^{-1}$, BSA-Cefoxitin; $K_1^{obs}$=7.24$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=1.13$\times$$10^3$ $M^{-1}$, BSA-Latamoxef; $K_1^{obs}$=8.87$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=1.92$\times$$10^3$ $M^{-1}$, BSA-Cefotetan; $K_1^{obs}$=15.41$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=2.7$\times$$10^3$ $M^{-1}$.