• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Current Trends in Toxicological Sciences
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• pp.92-92
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• 2002

• 한국미생물·생명공학회지
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• 제18권5호
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• pp.501-505
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• 1990

토양으로부터 분리한 Streptomyces 속 세균 KIS 13은 thiol 계통 단백질분해효소 활성을 특이적으로 저해하는 저분저량 저해물질을 생성하였다. 저해물질 생성은 세균체성장에 연관된 생성양상이 나타내었다. 배양액으로부토 butanol 추출, silicagel 60 column chromatography, Sephadex LH-2 gel-filtration chromatography, preparative HPLC 등의 과정을 통하여 단백질 분해효소 저해물질을 순수분리하였다. 이 저해물질은 Hammersten casein을 기질로 사용할때, papain에 대하여 non-competitive한 저해양상을 나타내었다.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.39-43
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• 1990

본 저해물질은 10Mug의 Alpha-D-glucosidase에 대해서 50Mug 및 100Mug을 첨가했을 때 저해율은 각각 60, 80 정도였으며 enzyme-inhibitor complex를 비교적 서서히 형성하여 5분간 진처리하였을 때 약 55의 저해율을 나타내었다. 그리고 Alpha-D-glucosidase, Alpha-galactosidase및 Beta-galactosidase를 제외한 탄수화물 분해효소에 대해서는 저해능이 없었으며, Alpha-D-glucosidase에 대한 저해양상은 non-competitive type 이었으며 Ki 값은 118 $\mu$g/m$\ell$였다.

• 미생물학회지
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• 제31권2호
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• pp.148-156
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• 1993

Kinetic parameters of purine nucleoside phosphorylase (PNP) from Saccharomyces cerevisiae were measured. The Michaelis constants determined for substrates of the enzyme were $ 2.0 * 10^{-4}$ M for inosine, $2.0 *10^{-3}$ M for deoxyinosine, $ 2.0 * 10^{-5}$ M for guanosine and $2.0 10 ^{-5}$ M for deoxyguanosine. According to the ratio of relative $K_{cat}$Km, substrate specificity of each nucleoside was in the order of guanosine or deoxyguanosine, inosine and deoxyinosine. Cosubstrate, phosphate, revealed downward curvature in Lineweaver-Burk plot at high concentrations, indicating a negative cooperativity between subunits. The inhibition constants for purine analogs were measured to be $ 6 * 10^{-4}$ M for formycin B as the competitive inhibitor of inosine, $ 9 * 10^{-6}$ M for guanine as the competitive inhibitor of guanosine, $2 * 10^{-4}$ M for hypoxanthine as the non competitive inhibitor of guanosine and $4.5 * 10 ^{-4}$ M for 6-mercaptopurine as the non competitive inhibitor of guanosine. Alternative substrates, guanosine, deoxyguanosine and adenosine were found to act as competitive inhibitors with Ki values o $f^ 2.0 * 10 {-5}$ M, $2.6 * 10^{-5}$ M and $8.5 * 10 ^{-4}$ M, respectively, when inosine was the variable substrate. Guanosine and deoxyguanosine were also observed as competitive inhibitors with the Ki values of $1.8 * 10^{-5}$ M and $ 3.0 * 10^{-5}$ M, respectively, when deoxyinesine was the variable substrate. The results of alternative substrate sstudies suggested that a single enzyme acted on different nucleosides, inosine, deoxyinosine, adenosine, guanosine and deoxyguanosine.e.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.152-158
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• 2016

글루탐산염(Glutamate)은 척추동물의 중추신경계에서 중요한 흥분성 신경전달물질 중의 하나이다. 글루탐산염의 대사를 조절하는 사람 글루탐산염 탈수소 효소(hGDH)는 정신분열증(schizophrenia) 환자의 대뇌에서 발현이 증가한다는 연구들이 있었다. 본 연구에서는 정신분열증과 연관된 항정신성약물인 haloperidol, risperidone, (${\pm}$)-sulpride, chlopromazine hydrochloride, melperone, (${\pm}$)butaclamol, domperidone, clozapine에 의한 hGDH의 효소활성변화를 확인하고자 하였다. 우선, 유전자 재조합을 통해 hGDH 동종효소 hGDH1, hGDH2를 합성하였다. 합성된 hGDH1과 hGDH2에 대한 항정신성약물의 억제효과를 효소검사법(enzyme assay)을 통해 확인한 결과, haloperidol, (${\pm}$)-sulpride, melperone, clozapine에 의해 hGDH1과 hGDH2의 효소활성이 억제되었다. 또한, 단백질 인산화 효소 측정법(kinase assay)을 하여 haloperidol이 기질인 알파-케토글루타르산에 대하여는 비경쟁적 저해반응(noncompetitive inhibition)을, NADH에 대하여서는 반경쟁적 저해반응(uncompetitive inhibition)이 나타는 것을 확인하였다. 입체성 다른 자리 작동체(allosteric effector)인 L-leucine이 다른 정신병치료제에서는 hGDH2의 억제를 회복시켰지만 오직 haloperidol에서는 효소의 활성이 회복되지 않았다. 따라서 본 연구는 hGDH1과 hGDH2 에서 항정신성약물에 의한 효소활성 억제를 비교하여 확인하였으며, 중추신경계에서 haloperidol이 GDH 활성 조절과 함께 글루탐산 농도를 조절할 수 있다는 가능성을 제시한다.

• KSBB Journal
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• 제11권3호
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• pp.276-287
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• 1996

하이브리도마 세포의 성장과 사망, 모노클론 항체의 생산, 포도당과 글루타민의 소비, 그리고 유산과 암모늄 이옹의 생산에 미치는 클루타민의 영 향을 조사하기 위해 초기 글루타민 농도를 변화시키면서 하이브리도마 세포의 회분식 현탁배양을 실시하였다. 실험 결과에 기초하여 세포의 성장속도, 영양물(포도당과 글루타민) 소비속도, 그리고 모노클론 항체 및 대사 부산물(유산과 암모늄이온)의 생산 속도를 예측할 수 있는 수학적 모델이 제시되었다. 포도당과 글루타민에 대해서는 중첩 적인 Monod 형식이며 암모늄 이옹과 유산에 대해 서는 Non-copmetitive inhibition 관계로 표시되는 세포의 비성장 속도에 관한 방정식이 개발되었다. 유산에 대한 억제 상수는 유산농도에 반바례하였다. 세포의 비사망 속도는 포도당, 글루타민, 암모 늄 이온과 유산 농도의 함수로 유도되었다.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.759-765
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• 2004

The NCS inhibited the activity of glucosyltransferase which was produced by Streptococcus mutans JC-2, and the rate of inhibition at $100\muM<$ and $200\muM$ were 74.0% and 99.8%, respectively. It was stable in alkali condition, but unstable in acid condition. It was also stable up to $80^{\circ}C$. The kinetic study of the inhibition by NCS was carried out by Lineweaver-Burk plot and Dixon plot. It was non-competitive inhibition, determined by the two plots and $K_i$ and $K_i$ values were $15\muM$ and $19.3\muM$ respectively. The NCS did not show cytotoxicity against human gingival cells at $K_i$ ($15\muM$, $150\muM$, $1,500\mu$ M) concentrations. It had less cytotoxicity than chlohexidin, which has usually been used as the agent of anticaries. To evaluate the industrial applicability of the NCS, human pluck tooth was used. The inhibitory rates of tooth calcification and calcium ion elution by the NCS were 41 % and 2.5 times, respectively. These results suggested that NCS from Bacillus sp. S-1013 is an efficient anticaries agent.

• Journal of Applied Biological Chemistry
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• 제49권3호
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• pp.110-113
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• 2006

Prolyl endopeptidase (PEP, EC 3.4.21.26, also referred to as prolyl oligopeptidase) degrades proline containing, biologically active neuropeptides such as vasopressin, substance P and thyrotropin-releasing hormone by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity. Therefore, a specific PEP inhibitor can be a good candidate of drug against memory loss. Upon our examination for PEP inhibitory activity from micronutrients, ascorbic acid (vitamin C) showed small but significant PEP inhibition (13% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$). Palmitic acid showed almost no PEP inhibition. However, 6-O-palmitoyl ascorbic acid ($\underline{1}$) showed 70% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$ indicating that hydrophobic portion of the compound $\underline{1}$ may facilitate the inhibitory effect. $IC_{50}$ value of compound $\underline{1}$ was $12.6{\pm}0.2{\mu}M$. The primary and secondary Lineweaver Burk and Dixon plots for compound $\underline{1}$ indicated that it is a non-competitive inhibitor with inhibition constant (Ki) value of $23.7{\mu}M$.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1697-1700
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• 2006

• KSBB Journal
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• 제23권3호
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• pp.239-244
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• 2008

For physiological function of aloe concentrate by ultrafiltration (UF) process, jack bean urease inhibitory activity and bentonite flocculating activity of UF aloe concentrate was investigated and compared with fresh aloe gel. Urease inhibitory activity of UF aloe concentrate ranged from 87 to 90% in 1 mL sample. Also, urease inhibitory activity of UF aloe concentrate increased about 10% by heat treatment showing the heat stability. From Lineweaver-Burk plot for UF aloe concentrate, urease inhibition pattern indicated general non-competitive inhibition. From flocculation test of UF aloe concentrate about 1% (w/v) bentonite suspension, maximum flocclulating activity of 97% was obtained at 0.5 mL addition of UF aloe concentrate/ 5 ml bentonite suspension. However, flocculating activity of 81% was obtained at 1 mL addition of UF aloe concentrate/ 5 mL bentonite suspension, which was typical flocculating behavior of polymers with re-dispersion at overdose area. FT-IR spectra of UF aloe concentrate showed the characteristic patterns of $\beta$-binding polysaccharide and less deacetylation indicating higher level of bioactive polysaccharide content.