• Archives of Pharmacal Research
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• v.15 no.1
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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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• v.48 no.4
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• pp.423-427
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• 2010

Carbon nano sphere(CNS) and nano bowl of carbon(NBC) containing 1.0 wt% copper were prepared by impregnation method and their catalytic activity was compared in the phenol hydroxylation with hydrogen peroxide in the presence of water and acetonitrile as a solvent, respectively. Cu content of catalysts was determined by EDS, and BET, pore volume, pore size and pore size distribution were compared. For both catalysts, phenol conversion, $H_2O_2$ efficiency and yield of catechol and hydroquinone were higher in the presence of water as a solvent than those in the presence of actonitrile. And catalytic activity such as phenol conversion and $H_2O_2$ efficiency of 1.0 Cu/CNS is about two times higher than that of 1.0 Cu/NBC in water solvent.

• Korean Journal of Pharmacognosy
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• v.28 no.3
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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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• v.30 no.11
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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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• v.43 no.2
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• pp.215-221
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• 2005

A Fe-containing mesoporous silica (Fe-MCM-41) in which part of Si in the framework was replaced by Fe(Si-O-Fe) has been successfully prepared using $Fe^{3+}$ salt by a direct synthesis route. Physical properties of the material were characterized by XRD, $N_2$ adsorption, SEM/TEM, UV-vis and FT-IR spectroscopies. Fe-MCM-41 exhibited high catalytic activity in phenol hydroxylation using $H_2O_2$ as oxidant, giving phenol conversion of ca. 60% at $50^{\circ}C$ [phenol : $H_2O_2$ = 1:1, water solvent]. Fe-MCM-41 was also applied to the growth of CNTs, utilizing a thermal-CVD reactor using acetylene gas, which demonstrated that multi-wall CNTs could be prepared efficiently using the Fe-MCM-41 catalyst.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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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.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.644-650
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• 1989

Syntheses of phthalide sulfone 2 and naphthalenone 6 followed by new ring annelation methodology of Michael addition using the sulfone anion developed by Hauser-Rhee, furnished linear tetracyclic ring system compound 11. The double bond existing in A-ring of 11 was used to convert to carbomethoxy compound 16, possessing one carbon atom more via Arndt-Eistert synthesis and Wolff rearrangement. Cyclization and hydroxylation of 16 completed the construction of (${\pm}$)-7-Deoxyaklavinone (18).

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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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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• v.27 no.3
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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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• v.31 no.1
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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.