• Applied Biological Chemistry
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• 제36권3호
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• pp.158-162
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• 1993

토양에서 분리한 bilirubin oxidase를 생산하는 Penicillium sp. LAM 91-89의 배양액으로부터 효소를 정제하여 여러가지 성질을 조사하였다. LAM 91-89 billirubin oxidase는 $ethanol(40{\sim}80%)$ 추출 및 2회의 Sephadex G-200 column chromatography로 약 70배 정제하였으며 회수율은 12%였다. 이 효소는 분자량이 약 53,000 dalton이었으며 $40^{\circ}C$, pH 8.5에서 최대의 활성을 보였고 pH 6에서 10까지의 넓은 범위와 $40^{\circ}C$ 이하에서 안정하였다. 또 효소의 활성이 $Mg^{2+}$에 의해서 증가하였으며 $Ag^+,\;Hg^{2+},\;Mn^{2+},\;Pb^{2+}$, p-CMB, iodoacetate 및 SDS에 의해서 저해되었다. 그리고 이 효소는 bilirubin에 대한 특이성이 컸으며 bilirubin에 대한 $K_m$값은 $6.67{\mu}M$이였다.

• Korean Chemical Engineering Research
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• 제59권3호
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• pp.373-378
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• 2021

본 연구는 땀에 존재하는 젖산을 연료로 사용하여 전기를 생산하는 웨어러블 연료전지용 고전력 젖산 산화효소 전극을 개발하는 데 그 목적이 있다. 유연성 있는 탄소종이 기반의 고정화효소 전극을 제작하고 평가하였다. 전해질 내 젖산농도 증가에 따라 젖산 산화효소(lactate oxidase, LOx)의 촉매작용으로 전류생성량이 증가하였다. 금 나노입자가 부착된 탄소종이에 고정화된 LOx가 탄소종이에 부착된 LOx보다 1.5배 많은 전류를 생성하였다. 빌리루빈 산화효소(bilirubin oxidase, BOD)가 고정화된 cathode는 질소로 퍼지(purge)된 전해질보다 산소로 포화된 전해질에서 높은 환원전류를 발생시켰다. 두 전극으로 구성된 연료전지를 제작하여 방전전류 변화에 따른 셀전압을 측정하였다. 방전 전류밀도 값이 66.7 ㎂/cm²에서 셀 전압은 0.5±0.0 V였고, 셀 전력량은 최대치인 33.8±2.5 ㎼/cm²를 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3118-3122
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• 2010

The water soluble redox polymer, poly(N-vinylimidazole) complexed with Os(4,4'-dichloro-2,2'-bipyridine)$_2Cl]^+$ (PVI-[Os(dCl-bpy)$_2Cl]^+$), was electrodeposited on the surface of a glassy carbon electrode by applying cycles of alternating square wave potentials between 0.2 V (2 s) and 0.7 V (2 s) to the electrode in a solution containing the redox polymer. The coordinating anionic ligand, $Cl^-$ of the osmium complex, became labile in the reduced state of the complex and was substituted by the imidazole of the PVI chain. The ligand substitution reactions resulted in crosslinking between the PVI chains, which made the redox polymer water insoluble and caused it to be deposited on the electrode surface. The deposited film was still electrically conducting and the continuous electrodeposition of the redox polymer was possible. When cycles of square wave potentials were applied to the electrode in a solution of bilirubin oxidase and the redox polymer, the enzyme was co-electrodeposited with the redox polymer, because the enzymes could be bound to the metal complexes through the ligand exchange reactions. The electrode with the film of the PVI-[Os(dCl-bpy)$_2Cl]^+$ redox polymer and the co-electrodeposited bilirubin oxidase was employed for the reduction of $O_2$ and a large increase of the currents was observed due to the electrocatalytic $O_2$ reduction with a half wave potential at 0.42 V vs. Ag/AgCl.

• 공업화학
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• 제24권1호
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• pp.99-103
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• 2013

유리화탄소전극 위에 탄소나노튜브(CNT), 전하전달체(CTC), 글루코스 산화효소(GOx), 폴리이온복합체(PIC, poly-L-lysine hydrobromiderhk과 poly(sodium 4-styrenesulfonate) 혼합물)를 순차적으로 도포하여 글루코스/산소 바이오전지용 효소전극을 제조하였다. 또한, CNT, bilirubin oxidase (BOD), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 그리고 PIC 등의 층으로 제조한 전극을 바이오캐쏘드로 사용하여 바이오전지를 제조하였다. CNT와 CTC가 전극의 성능에 미치는 영향을 조사하였으며, 글루코스농도 5, 20, 200 mM에서 각각 3.6, 10.1, $46.5{\mu}W/cm^2$의 최대전력밀도를 나타내었으며, 본 연구에서 제시한 전극이 바이오전지 및 바이오센서의 개발에 활용될 수 있다는 것을 보여주었다.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2803-2808
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• 2014

High potential and fast electron transfer of a cathode mediator are significant factors for improving the performance of biofuel cells. This paper reports the first synthesis of a cathode redox polymer that is a coordination complex of poly (acrylic acid-vinylpyridine-acryl amide) (PAA-PVP-PAA) and [Os(4,4'-dicarboxylic acid-2,2'-bipyridine)$_2Cl_2]^{/+}$ ($E^{\circ}=0.48V$ versus Ag/AgCl). Bilirubin oxidase can be easily incorporated into this polymer matrix, which carried out the four-electron oxygen under typical physiological conditions (pH 7.2, 0.14 M NaCl, and $37^{\circ}C$). This new polymer showed an approximately 0.1 V higher redox potential than existing cathode mediators such as PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. In addition, we suggest increasing the polymer solubility with two hydrophilic groups present in the polymer skeleton to further improve fast electron transfer within the active sites of the enzyme. The maximum power density achieved was 60% higher than that of PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. Furthermore, high current density and electrode stability were confirmed for this osmium polymer, which makes it a promising candidate for high-efficiency biofuel cells.

• 전기화학회지
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• 제7권1호
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• pp.44-48
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• 2004

The two-component type enzyme amplified amperometric DNA assay is described to use an ambient $O_2$ of the substrate of the DNA labeling enzyme. Although the assay detects DNA only at > 0.5M concentration, a concentration $\~10^6$ fold higher than the sandwich-type enzyme amplified amperometric DNA assay, it can be run with an always available substrate. The assay utilizes screen-printed carbon electrodes (SPEs) which were pre-coated by a co-electrodeposited film of an electron conducting redox hydrogel and a 37-base long single-stranded DNA sequence. The DNA in the electron conducting film hybridizes and captures, when present, the 37-base long detection-DNA, which is labeled with bilirubin oxidase (BOD), an enzyme catalyzing the four-electron reduction of $O_2$ to water. Because the redox hydrogel electrically connects the BOD reaction centers to the electrode, completion of the sandwich converts the film from non-electrocatalytic to electrocatalytic for the reduction of $O_2$ to water when the electrode is poised at 200 mV vs. Ag/hgCl. The advantage or the assay over the earlier reported sandwich type enzyme amplified amperometric DNA assay, in which the amplifying enzyme was horseradish peroxidase, is that it utilizes ambient $O_2$ instead of the less stable and naturally unavailable $H_2O_2$.

• 생명과학회지
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• 제12권3호
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• pp.332-339
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• 2002

옻나무(Rhus verniciflua Stokes)로부터 간섬유화에 따른 간독성의 경감기전을 추구할 목적으로 ethyl acetate 분획에서 분리한 fustin 및 sulfuretin을 실험동물에 투여하고서 혈액학적 변화 및 간장 중 활성산소에 미치는 영향 검토한 결과 담도결찰하여 간섬유화를 유도한 군에서는 AST, ALT, SDH, ${\gamma}$-GT활성 및 total bilirubin의 양이 현저히 증가되던 것이 옻나무의 메탄을 엑스(250 mg/kg), 에틸아세테이트 엑스(250 mg/kg), fustin(10 mg/kg) 및 sulfuretin(10 mg/kg)을 2주간 각각 경구투여 하므로서 유의성 있게 억제되었다. Hydroxyproline양 및 MDA 농도에서도 간섬유화를 유도하므로서 현저히 증가되던 것이 옻나무의 분획 및 sulfuretin과 fustin의 투여로서 각각 약 60% 및 47%정도 감소되었다. 간섬유화를 유도한 cytosolic계 효소인 xanthine oxidase 및 aldehyde oxidase의 활성이 현저히 증가되었으며 한편 superoxide dismutase, glutathione peroxidase 및 catalase은 간섬유화의 유도로 감소되었으나 옻나무의 분획(메탄올, 에틸아세테이트) 및 성분(fustin, sulfuretin)의 투여로서 조절되었다.

• Korean Chemical Engineering Research
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• 제62권3호
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• pp.238-245
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• 2024

젖산 전극은 환자의 건강상태와 스트레스 수준, 및 운동선수의 피로도를 실시간으로 모니터링하는 젖산 센서 또는 젖산 연료전지 전극으로 활용될 수 있다. 본 연구에서는 젖산 산화효소, 카탈라아제, 미토콘드리아로 구성된 고성능 전극을 제작하고 전극의 표면분석 및 전기화학적 특성을 조사하였다. 단일벽 탄소나노튜브로 개질된 탄소종이(CPSWCNT)는 개질 전보다 전기 전도성이 크게 향상되었다. 젖산 산화효소, 카탈라아제, 그리고 미토콘드리아가 부착된 전극(CP-SWCNT-LOx-Cat-Mito)은 젖산 산화효소와 카탈라아제가 부착된 전극에 비하여 많은 전류를 생산하였다. 빌리루빈 산화효소(BOD)가 부착된 전극(CP-SWCNT-BOD)이 생산하는 환원전류량은 전해질의 산소 존재 유무에 따라 크게 영향을 받았다. CP-SWCNT-LOx-Cat-Mito (anode)와 CP-SWCNT-BOD (cathode)로 구성된 연료전지는 133 ㎂/cm²로 방전 시 0.2 V의 셀 전위를 유지하며 29 ㎼/cm²의 전력을 생산하였다. 본 연구결과는 미토콘드리아가 젖산 센서 및 연료전지 성능 향상에 필수적인 생체물질임을 시사한다.

• 대한한방내과학회지
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• 제44권3호
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• pp.402-417
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• 2023

Objective: Liver fibrosis is a highly conserved wound-healing response and the final common pathway of chronic inflammatory injury. This study aimed to evaluate the potential anti-fibrotic effect of the combination of Rhei Radix et Rhizoma water extract (RW) and silymarin in a thioacetamide (TAA)-induced liver fibrosis model. Methods: The liver fibrosis mouse model was established through the intraperitoneal injection of TAA (1 week 100 mg/kg, 2-3 weeks 200 mg/kg, 4-8 weeks 400 mg/kg) three times per week for eight weeks. Animal experiments were conducted in five groups; Normal, Control (TAA-induced liver fibrosis mice), Sily (silymarin 50 mg/kg), RSL (RW 50 mg/kg+silymarin 50 mg/kg), and RSH (RW 100 mg/kg+silymarin 50 mg/kg). Biochemical analyses were measured in serum, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA), and ammonia levels. Liver inflammatory cytokines and fibrous biomarkers were measured by Western blot analysis, and liver histopathology was evaluated through tissue staining. Results: A significant decrease in the liver function markers AST and ALT and a reduction in ammonia and total bilirubin were observed in the group treated with RSL and RSH. Measurement of reactive oxygen species and MDA revealed a significant decrease in the RSL and RSH administration group compared to the TAA induction group. The expression of extracellular matrix-related proteins, such as transforming growth factor β1, α-smooth muscle actin, and collagen type I alpha 1, was likewise significantly decreased. All drug-administered groups had increased matrix metalloproteinase-9 but a decreasing tissue inhibitor of matrix metalloproteinase-1. RSL and RSH exerted a significant upregulation of NADPH oxidase 2, p22^phox, and p47^phox, which are oxidative stress-related factors. Furthermore, pro-inflammatory proteins such as cyclooxygenase 2 and interleukin-1β were markedly suppressed through the inhibition of nuclear factor kappa B activation. Conclusions: The administration of RW and silymarin suppressed the NADPH oxidase factor protein level and showed a tendency to reduce inflammation-related enzymes. These results suggest that the combined administration of RW and silymarin improves acute liver injury induced by TAA.