• Archives of Pharmacal Research
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• 제15권1호
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• pp.41-47
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• 1992

In order to obtain acetaminophen, a popular analgesic-antipyretic, though microbial p-hydroxylation and N-acetylation of aniline, various Streptomyces strains were screened. Aniline N-acetylation activity was rather ubiquitous but-hydroxylation activity was selective. Microbial conversion pathway of aniline to acetaminophen was considered to be through N-acetylation and p-hydroxylation or vice versa. However, depending on species used, o-hydroxylation and its degradation activity (S. fradiae) and acetaminophen degradation activity (S. coelicolar) were also detected. Among the screened Streptomyces strains, S fradiae NRRL 2702 showed the highest acetanilide p-hydroxylation activity (203% conversion rate). Furthermore, in S. fradiae carbon source and its concentration, phosphate ion concentration and pH of growth medium were found to play the crucial roles in p-hydroxylation activity. Through the proper combination of factors mentioned above, the ten times more activity (26-30% conversion rate) was attained.

• Korean Chemical Engineering Research
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• 제48권4호
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• pp.423-427
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• 2010

나노구조를 갖는 중공구형(CNS) 및 중공반구형(NBC) 다공성 탄소 담체에 각각 약 1.0 wt%의 구리를 담지시켜 두 종류의 촉매를 제조하였고 과산화수소수에 의한 페놀의 수산화 반응에서 촉매의 성능을 두 종류의 서로 다른 용매(물, 아세토니트릴)에 대하여 비교 분석하였다. 촉매에 담지된 구리의 양은 EDS 분석으로 확인하였고 비표면적, 기공 부피, 기공 분포도 등을 비교 분석하였다. 두 종류의 촉매에서 모두 아세토니트릴보다 물에서 더 높은 전환율과 과산화수소 유효도 및 카테콜과 하이드로퀴논의 생성율을 얻을 수 있었고, 물을 용매로 사용했을 때 1.0 Cu/CNS 촉매가 1.0 Cu/NBC 촉매보다 50% 이상의 전환율과 과산화수소 유효도를 보였다.

• 생약학회지
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• 제28권3호
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• pp.156-161
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• 1997

For the search of hepatoprotective compounds from the folk medicines, 14 natural products which have been traditionally used as hepatoprotective drugs in Korea were extracted with methanol. The extracts were screened for the antioxidant activity on lipid peroxidation induced by Fenton reaction in rat homogenate and Ac2F cell toxicity by t-hydroperoxide. Dendrobium moniliforme and Castanea crenata were chosen for the further investigation and its therapeutic effects on the liver damage induced by carbon tetrachloride in rats were evaluated. Oral administration of the extracts reduced the aspartate aminotransferase(AST) and alanine aminotransferase(ALT) activities in the serum of the carbon tetrachloride intoxicated rat. And the treatment of the extracts prevented the decrease of aminopyrine N-demethylation and aniline hydroxylation activities of the carbon tetrachloride-intoxicated rat liver. These results suggest that oral administration of Dendrobium moniliforme and Castanea crenata is effective in recovering the liver function in $CCl_4-treated$ rats.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1750-1759
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• 2020

The characterization of cytochrome P450 CYP125A13 from Streptomyces peucetius was conducted using cholesterol as the sole substrate. The in vitro enzymatic assay utilizing putidaredoxin and putidaredoxin reductase from Pseudomonas putida revealed that CYP125A13 bound cholesterol and hydroxylated it. The calculated K_D value, catalytic conversion rates, and Km value were 56.92 ± 11.28 μM, 1.95 nmol min^-1 nmol^-1, and 11.3 ± 2.8 μM, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that carbon 27 of the cholesterol side-chain was hydroxylated, characterizing CYP125A13 as steroid C27-hydroxylase. The homology modeling and docking results also revealed the binding of cholesterol to the active site, facilitated by the hydrophobic amino acids and position of the C27-methyl group near heme. This orientation was favorable for the hydroxylation of the C27-methyl group, supporting the in vitro analysis. This was the first reported case of the hydroxylation of cholesterol at the C-27 position by Streptomyces P450. This study also established the catalytic function of CYP125A13 and provides a solid basis for further studies related to the catabolic potential of Streptomyces species.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.215-221
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• 2005

실리카계 메조 물질인 MCM-41의 합성시 $Fe^{3+}$ 염을 합성 기질에 직접 도입하여 구조 내의 Si를 Fe로 일부 치환시킨 Fe-MCM-41(4 mol% Fe)을 합성하였다. XRD, $N_2$ 흡착법, TEM 등으로 합성한 메조 세공 물질의 구조적 특성을 조사하였으며, UV-Vis 및 FT-IR 등의 분광분석을 통하여 철의 상태를 확인하였다. 촉매적 활성 연구를 위하여 과산화수소를 산화제로 이용한 phenol hydroxylation을 수행하였으며, 물을용매로 반응 온도 $50^{\circ}C$, phenol:$H_2O_2$=1:1 조건에서 ca. 60%의 전화율을 얻었다. 또한, 구조 중 Fe 활성점을 이용한 탄소 나노 튜브의 성장 가능성을 확인하기 위하여, 아세틸렌가스를 탄소원으로 사용한 thermal-CVD 반응기를 이용하였으며, 다중벽 탄소 나노 튜브를 제조할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.287-293
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• 2022

The hydroxylation of methane (CH₄) is crucial to the field of environmental microbiology, owing to the heat capacity of methane, which is much higher than that of carbon dioxide (CO₂). Soluble methane monooxygenase (sMMO), a member of the bacterial multicomponent monooxygenase (BMM) superfamily, is essential for the hydroxylation of specific substrates, including hydroxylase (MMOH), regulatory component (MMOB), and reductase (MMOR). The diiron active site positioned in the MMOH α-subunit is reduced through the interaction of MMOR in the catalytic cycle. The electron transfer pathway, however, is not yet fully understood due to the absence of complex structures with reductases. A type II methanotroph, Methylosinus sporium 5, successfully expressed sMMO and hydroxylase, which were purified for the study of the mechanisms. Studies on the MMOH-MMOB interaction have demonstrated that Tyr76 and Trp78 induce hydrophobic interactions through π-π stacking. Structural analysis and sequencing of the ferredoxin domain in MMOR (MMOR-Fd) suggested that Tyr93 and Tyr95 could be key residues for electron transfer. Mutational studies of these residues have shown that the concentrations of flavin adenine dinucleotide (FAD) and iron ions are changed. The measurements of dissociation constants (K_ds) between hydroxylase and mutated reductases confirmed that the binding affinities were not significantly changed, although the specific enzyme activities were significantly reduced by MMOR-Y93A. This result shows that Tyr93 could be a crucial residue for the electron transfer route at the interface between hydroxylase and reductase.

• 대한화학회지
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• 제33권6호
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• pp.644-650
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• 1989

Phthalide sulfone 2와 naphthalenone 6을 만들어서 Hauser-Rhee가 개발한 Michael addition의 새로운 고리 접합법으로 4개의 선형 고리화합물의 구조를 갖는 tetracyclic 화합물 11을 만들었다. 화합물 11의 ring A가 갖고 있는 중요한 이중결합을 이용해서 탄소수가 한 개 증가된 carbomethoxy 화합물 16으로 변형시키는 것은 Arndt-Eistert, Wolff rearrangement를 이용하였다. 그리고 나서 이들을 고리화 반응시킨 뒤 hydroxylation시켜서 최종 생성물인 (${\pm}$)-7-Deoxyaklavinone(18)를 합성하였다.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.147-149
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• 1999

Biotransformation of exogenous (-)-(4R)-isopiperitenone in cell suspension cultures of Mentha piperita resulted in oxidized products, with (-)-7-hydroxyisopiperitenone being the major compound. The mass of products obtained $unde^{18}O_2$, atmosphere was two units higher than that under normal atmosphere. The biotransformation was inhibited by several cytochrome P450-specific inhibitors as well as by carbon monoxide. Carbon monooxide inhibition was substantially overcome by irradiation of cells with blue light including light at 450nm wavelength. These results suggested that a cytochrome P450-type monooxygenase was involved in the biotransformation.

• Journal of Pharmaceutical Investigation
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• 제27권3호
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• pp.173-179
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• 1997

A water-soluble DDB derivative (Bis{2-(methylamino)ethyl}-4,4-dimethoxy-5,5',6,6'-dimethylenedioxy-biphenyl-2,2'-dicarboxylate, DDB-S) was synthesized and its therapeutic effects on the liver damage induced by carbon tetrachloride in rats were evaluated. Oral administration of DDB-S reduced the aspartate aminotransferase(AST) and alanine aminotransferase(ALT) activities and increased total protein and albumin contents in the serum of the carbon tetrachloride intoxicated rat. Therapeutic effects of DDB-S by intravenous injection was also investigated using carbon tetrachloride intoxicated rats. Histological studies showed that IV injection of DDB-S had improved the typical necrosis around centrilobular area in liver tissue due to the carbon tetrachloride intoxication and also prevented the elevation of liver weigh/body weight ratio. IV administration of DDB-S to $CCl_4-treated$ rats significantly decreased AST & ALT activities and also prevented the decrease of aniline hydroxylation activity of the liver. These results indicate that i.v. administration of DDB-S is very effective in recovering the liver function in $CCl_4-treated$ rats.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.82-88
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• 2023

Genomic analysis indicated that the genome of Drosophila melanogaster contains more than 80 cytochrome P450 genes. To date, the enzymatic activity of these P450s has not been extensively studied. Here, the biochemical properties of CYP6A8 were characterized. CYP6A8 was cloned into the pCW vector, and its recombinant enzyme was expressed in Escherichia coli and purified using Ni²⁺-nitrilotriacetate affinity chromatography. Its expression level was approximately 130 nmol per liter of culture. Purified CYP6A8 exhibited a low-spin state in the absolute spectra of the ferric forms. Binding titration analysis indicated that lauric acid and capric acid produced type I spectral changes, with K_d values 28 ± 4 and 144 ± 20 µM, respectively. Ultra-performance liquid chromatography-mass spectrometry analysis showed that the oxidation reaction of lauric acid produced (ω-1)-hydroxylated lauric acid as a major product and ω-hydroxy-lauric acid as a minor product. Steady-state kinetic analysis of lauric acid hydroxylation yielded a k_cat value of 0.038 ± 0.002 min^-1 and a K_m value of 10 ± 2 µM. In addition, capric acid hydroxylation of CYP6A8 yielded kinetic parameters with a k_cat value of 0.135 ± 0.007 min^-1 and a K_m value of 21 ± 4 µM. Because of the importance of various lipids as carbon sources, the metabolic analysis of fatty acids using CYP6A8 in this study can provide an understanding of the biochemical roles of P450 enzymes in many insects, including Drosophila melanogaster.