• Bulletin of the Korean Chemical Society
• /
• 제19권6호
• /
• pp.689-695
• /
• 1998

Carbobenzoxy-alanyl-thiaarginine benzyl ester and carbobenzoxy-alanyl-thialysine benzyl ester were synthesized in solution. Kinetic studies were carried out using three different analytical methods, semi-classical method, progress curve analysis and competitive spectrophotometry. In competitive spectrophotometry, carbobenzoxy-valyl-glycyl-arginyl-p-nitroaniline was used as a detector. Kinetic constants such as $K_m$ and $V_{max}$ measured by competitive spectrophotometry are almost the same as those values measured by semi-classical method. Colorimetric Ellman's assays showed the thio-peptido mimetics to be a suitable substrates for trypsin. Kinetic studies with trypsin gave $K_m$ of 2.33 mM and $k_{cat}$ of $1.50{\times}10^5\;min^{-1}$ for carboxy-alanyl-thiaarginine benzyl ester and $K_m$ of $3.41{\times}10^{-3}\; Mm\; and\; k_{cat}\; of\; 520{\times}102\; min^{-1}$ for carbobenzoxy-alanyl-thialysine benzyl ester, respectively. Kinetic constants $(K_m=2.04{\times}10^{-2}\; mM, K_{cat}=4.42{\times}10^3 \;min^{-1})$ for natural substrate, carbobenzoxy-alanyl-lysine benzyl ester, were also evaluated by competitive spectrophotometry in order to compare the mode of binding on trypsin.

• Archives of Pharmacal Research
• /
• 제20권4호
• /
• pp.324-329
• /
• 1997

AB-type amphiphilic copolymers (abbreviated as LE) composed of poly (L-leucine) (PLL) as the A component and poly (ethylene oxide) (PEO) as the B component were synthesized by the ring-opening polymerization of L-leucine N-carboxy-anhydride initiated by methoxy polyoxyethylene amine $(Me-PEO-NH_2)$ and characterized. Core-shell type nanoparticles were prepared by the diafiltration method. Particle size distribution obtained by dynamic light scattering was dependent on PLL composition and the size for LE-1, LE-2 and LE-3 was $369.6{\pm}267$, $523.4{\pm}410$ and $561.2{\pm}364 nm$, respectively. Shapes of the nanoparticies observed by transmission electron microscope (TEM) were almostly spherical. The critical micelle concentration (CMC) of the nanoparticles determined by a fluorescence probe technique was dependent on the composition of hydrophobic PLL, and the CMC for LE-1, LE-2 and LE-3 was $2.0{\times}10^{-6},1.7{\times}10^{-6}$ and $1.5{\times}10^{-6}(mol/l) $, respectively. Clonazepam release from core-shell type nanoparticles in vitro was dependent on PLL composition and drug loading content.

• 약학회지
• /
• 제46권5호
• /
• pp.313-319
• /
• 2002

Synthesis of 7$\beta$-[(Z)-2-(2-aminothiazol-4-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-[[(3S, 5S)-5-[4-phenyl-5-(4-methylphenyl or 2-thiophenyl)-4H-l, 2, 4- triazol-3-yl]thiomethylpyrrolidin-3-yl]]thiomethyl-3-cephem-4-carboxylic acids (7a, 7b) were described. (2S, 4S)-4-acethylthio-2-[4-phenyl-5-(4-methylphenyl or 2-thiophenyl)-4 H-1, 2, 4-triazol-3-yl]thiomethyl-1-tert-butoxycarbonylpyrrolidines (4a, 4b) were prepared from trans-4-hydroxy-L-proline with (2S, 4R)-absolute configuration as starting material. 4-Phenyl-5-(4-methylphenyl or 2-thiophenyl)-4 H-l, 2, 4-triazol-3-thiols (2a, 2b) were prepared from p-toluic anhydride and 2-thiophene carboxylic acid hydrazide, respectively. p-Methoxybenzyl 7$\beta$-(Z)-2-(2-for-mamidothiazol-4-yl)-2-(1-tert-butoxycarbonylisopropylimino]acetamido-3-[[ (3S, 5S)-5-[4-phenyl-5-(4-methylphenyl or 2-thio phenyl)-4H-1, 2, 3-triazol-3-yl]thiomethyl-1- tert-butoxycarbonylpyrrolidin-3-yl]]thiomethyl-3-cephem-4-carboxylates (6a, 6b) were achieved by using p-methoxybenzyl ]7P-(Z)-2-(2-formamidothiazol-4-yl)-2-(tert-butoxycarbonylisopropylimino] acetamido-3-chloromethyl-3-cephem-4-carboxylate (5) and (2S, 4S)-4-acethylthio-2-[4-phenyl-5-(4-methyl phenyl or 2-thiophenyl)-4H-1, 2, 4-triazol-3-yl]thiomethyl-1-tert-butoxycarbonyl pyrrolidines (4a, 4b). Removal of formyl, Boc, and p-methoxybenzyl protecting groups were carried out by triflu oroacetic acid and anisole to give the target compounds.

• BMB Reports
• /
• 제44권6호
• /
• pp.375-380
• /
• 2011

Bacillus licheniformis SK-1 naturally produces chitinase 72 (CHI72) with two truncation derivatives at the C-terminus, one with deletion of the chitin binding domain (ChBD), and the other with deletions of both fibronectin type III domain (FnIIID) and ChBD. We constructed deletions mutants of CHI72 with deletion of ChBD (CHI72${\Delta}$ChBD) and deletions of both FnIIID and ChBD (CHI72${\Delta}$FnIIID${\Delta}$ChBD), and studied their activity on soluble, amorphous and crystalline substrates. Interestingly, when equivalent amount of specific activity of each enzyme on soluble substrate was used, the product yield from CHI72-${\Delta}$ChBD and CHI72${\Delta}$FnIIID${\Delta}$ChBD on colloidal chitin was 2.5 and 1.6 fold higher than CHI72, respectively. In contrast, the product yield from CHI72${\Delta}$ChBD and CHI72${\Delta}$FnIIID-${\Delta}$ChBD on ${\beta}$-chitin reduced to 0.7 and 0.5 fold of CHI72, respectively. These results suggest that CHI72 can modulate its substrate specificities through truncations of the functional domains at the C-terminus, producing a mixture of enzymes with elevated efficiency of hydrolysis.

• 약학회지
• /
• 제57권6호
• /
• pp.388-393
• /
• 2013

Previously, we have reported that lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, increased melanin synthesis through intracellular $Ca^{2+}$ release in B16 cells. In this study we investigated the possible involvement of nitric oxide (NO) in the mechanism of lovastatin-induced melanogenesis. Lovastatin elevated NO formation in a dose-dependent manner. Treatment with mevalonate, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), precursors of cholesterol, did not significantly alter the lovastatin-induced NO production, suggesting that inhibition of cholesterol metabolism may not be involved in the mechanism of this action of lovastatin. Both NO formation and melanogenesis induced by lovastatin was significantly suppressed by treatment with $N^G$-nitro-L-arginine methyl ester (L-NAME) and 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide (cPTIO), an inhibitor of NO synthase and a NO scavenger, respectively. The lovastatin-induced NO production was significantly affected not by EGTA, an extracellular $Ca^{2+}$ chelator, but by an intracellular $Ca^{2+}$ chelator (BAPTA/AM) and intracellular $Ca^{2+}$ release blockers (dantrolene and TMB-8). Taken together, these results suggest that lovastatin may induce melanogenesis through NO formation mediated by intracellular $Ca^{2+}$ release in B16 cells. These results further suggest that lovastatin may be a good candidate for the therapeutic application of various hypopigmentation disorders.

• Journal of Microbiology
• /
• 제43권6호
• /
• pp.516-522
• /
• 2005

The phosphorylation of C-terminal domain (CTD) of Rpb1p, the largest subunit of RNA polymerase II plays an important role in transcription and the coupling of various cellular events to transcription. In this study, its role in DNA damage response is closely examined in Saccharomyces cerevisiae, focusing specifically on several transcription factors that mediate or respond to the phosphorylation of the CTD. CTDK-1, the pol II CTD kinase, FCP1, the CTD phosphatase, ESS1, the CTD phosphorylation dependent cis-trans isomerase, and RSP5, the phosphorylation dependent pol II ubiquitinating enzyme, were chosen for the study. We determined that the CTD phosphorylation of CTD, which occurred predominantly at serine 2 within a heptapeptide repeat, was enhanced in response to a variety of sources of DNA damage. This modification was shown to be mediated by CTDK-1. Although mutations in ESS1 or FCP1 caused cells to become quite sensitive to DNA damage, the characteristic pattern of CTD phosphorylation remained unaltered, thereby implying that ESS1 and FCP1 play roles downstream of CTD phosphorylation in response to DNA damage. Our data suggest that the location or extent of CTD phosphorylation might be altered in response to DNA damage, and that the modified CTD, ESS1, and FCP1 all contribute to cellular survival in such conditions.

• 한국세라믹학회지
• /
• 제42권4호
• /
• pp.260-268
• /
• 2005

규조토를 주원료로 사용한 서로 다른 조성비의 세라믹 슬러리를 압출성형하여 내열보호관을 제조하고, 기계적 강도, 미세구조, 탄소분석을 하였다. 입도가 $50\~100\;{\mu}m$ 다공성 규조토를 $60wt\%$로 고정하고, 조성물 변수로써 유$\cdot$무기바인더로 silica sol$(4.3\~7.3\;wt\%)$, CMC(Sodium CarboxyMethyl Cellulose $(6\~9\;wt\%)$) 및 paper powder$(4.7\~7.7\;wt\%)$를 $1\;wt\%$씩 변화시켜 최적의 배합비를 얻었다. 시편의 특성을 조사한 결과, 규조토 $60\;wt\%$에 silica sol $5.3\;wt\%$, CMC $7\;wt\%$를 첨가하였을 경우, 꺽임강도 7.12 MPa, 탄성율 1090 MPa, 압축강도 1.47 MPa, 탄소 $2.3\;wt\%$ 이하로 철강산업에서의 온도$\cdot$성분측정 및 sample 채취를 할 수 있는 용융금속 프로브용 규조토 내열보호관을 제조할 수 있었다.

• 한국환경농학회지
• /
• 제16권4호
• /
• pp.365-372
• /
• 1997

콩과 옥수수에서 glutatione-S-transferases와 carboxylesterase의 생화학적 특성과 quizalofopethyl 처리에 따른 식물체내 효소의 활성 변화를 조사한 결과는 다음과 같다. GSTS의 최적 pH는 8.2이고, Km값은 콩 $6.7{\times}10^{-3}M$, 옥수수 $2.5{\times}10^{-3}M$이었으며, Vmax는 콩 50nmole/mg/min, 옥수수 20nmole/mg/min이었다. Carboxylesterase의 최적 pH는 6.2${\sim}$7.0 범위이고, Km값은 콩 $4.2{\times}10^{-4}M$, 옥수수 $2.5{\times}10^{-4}M$이었으며, Vmax는 콩 33 nmole/mg/min, 옥수수 10nmole/mg/min이었다. 콩과 옥수수에 살포된 quizalofop-ethyl은 콩과 옥수수의 GSTs와 carboxy-lesterase의 활성을 감소시켰고, quizalofop-ethyl 80ppm을 처리했을때 콩은 10일이 경과후 회복되었지만, 옥수수는 3일이 경과후 고사하였다.

• 한국잡초학회지
• /
• 제6권1호
• /
• pp.25-32
• /
• 1986

생장조절물질(生長調節物質) Callus 유도(誘導)에 미치는 영향(影響)을 구명(究明)키 위하여 식물체(植物體)의 종자(種子) 또는 Shoot-tip으로부터 Callus 유도(誘導)를 검정(檢定), 유도(誘導)된 Callus로부터 식물체분화(植物體分化), 제초제(除草劑)가 Callus 생체중량증가(生體重量增加)에 미치는 영향(影響) 및 Succinate dehydrogenase의 TTC 반응검정(反應檢定)을 하여 얻어진 결과(結果)는 다음과 같다. 1. MS 기본배지(基本培地)에 2,4-D 함량(含量)은 올방개와 너도방동산이의 종자(種子)는 1.0ppm, 너도방동산이의 shoot-tip은 4.0pm, 삼강벼와 물피에서는 2ppm이 Callus 유도(誘導)를 위한 과정농도(過定濃度)였다. 2. MS기본배지(基本培地)에다 2,4-D와 BA와 TIBA를 첨가시(添加時) BA는 2,4-D 단독처리(單獨處理)보다 억제적(抑制的)이나 TIBA 처리(處理)는 0.3 또는 0.5ppm 첨가구(添加區)가 2,4-D 단독처리구(單獨處理區)보다 효과적(效果的)이었다. 삼강벼, 물피, 너도방동산이 종자(種子) 및 올방개 shoot-tip에서는 2,4-D 1.0ppm+TIBA 0.5ppm, 너도방동산이 shoot-tip에서는 2,4-D 1.0ppm+TIBA 0.3ppm 일 때가 가장 높았다. 3. Callus로부터 식물체분화율(植物體分化率)은 2,4-D에 Kinetin 첨가구(添加區)가 NAA에 Kinetin 첨가구(添加區)보다 효과적(效果的)이었고 물피는 2,4-D 0.8ppm+Kinetin 8.0 ppm에서 50%, 올방개는 2,4-D 1.6ppm+Kinetin 16.0ppm에서 33.3%가 분화(分化)가 되었으나 너도방동산이는 분화(分化)가 되지 않았다. 4. 제초제(除草劑) Londax 및 Basta는 농도(濃度)가 증가(增加)될수록 삼강벼, 물피, 올방개 및 너도방동산이의 Callus 유도(誘導) 또는 증식(增殖)을 억제(抑制)시켰고 $10^{-3}$M에서는 거의 100%가 억제(抑制)되었으나 저농도(低濃度)에서는 식물체간(植物體間)에 상이(相異)한 반응(反應)을 보였으며 양제초제(兩除草劑])에서 삼강벼가 물피나 너도방동산이보다 내성(耐性)을 보였다. 5. TTC에 대(對)한 Succinate dehydrogenase의 반응(反應)은 공시식물(供試植物)의 전(全) Callus가 모든 처리구(處理區)에서 정반응(正反應)(+)을 보여서 Callus가 생존(生存)해 있음을 알 수 있었다.

• 한국식품영양과학회지
• /
• 제43권4호
• /
• pp.516-521
• /
• 2014

야관문 추출물의 피부재생능력을 알아보고, 창상을 유발한 실험동물 모델에서 창상 치유 효과를 검증하고자 6개 군(NO, CO, PC, LCL, LCM, LCH)으로 나누어 5주간 실험하였다. Elastase 저해 활성을 평가한 결과 LCM군에서 항산화제인 BHA보다 2.7%($52.39{\pm}4.52$ vs $53.88{\pm}1.85$) 낮은 수치를 나타내었으며, collagenase 저해 활성을 평가한 결과 LCM군에서 BHA보다 7%($37.68{\pm}2.91$ vs $35.19{\pm}7.80$) 더 높은 활성을 나타내었다. 창상유발 21일에 LCL군, LCM군 및 LCH군의 왼쪽 창상 면적은 CO군과 비교하여 각각 54.2%, 53.5% 및 48.7% 현저한 창상면적 감소를 보였다. 이로서 야관문 추출물은 피부상피조직의 재생과 교원질의 합성을 도와 외과적 창상에 치료 효과가 있는 것으로 판단된다.