• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1489-1496
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• 2009

This study was done for the determination and excretion profile of adrenosterone and its metabolites in human urine using both liquid chromatography with atmospheric pressure chemical ionization mass spectrometry and gas chromatography with mass spectrometry. Adrenosterone and its two metabolites were detected in human urine after administration a healthy volunteer with 75 mg of adrenosterone. We found that adrenosterone-M1 ($C_{19}H_{26}O_3$) was a reduction and adrenosterone-M2 ($C_{19}H_{26}O_4$) was a hydroxylation at C-ring, which did not know the exact position of the C-ring. The adrenosterone parent was detected by GC/TOF-MS, but not detected by LC/APCI/MS because of low intensity. Adrenosterone and its two metabolites were excreted as their glucuronided fractions. The recovery of this method ranged from 100.7 to 118.4% and the reproducibility and accuracy test were 85.5 to 112.0% and 1.1 to 8.4%, respectively. The excretion studies showed that adrenosterone and its metabolites were detectable in human urine during a 48 h period after oral administration, with maximum level of excretion at 4.1 h. The glucuro-/sulfaconjugated ratio of adrenosterone, M1 and M2 was 0.73 ${\pm}$ 0.03, 0.96 ${\pm}$ 0.06 and 0.89 ${\pm}$ 0.03 (n = 6), respectively. The amounts of adrenosterone excreted in urine were 14.75 ng for 48 h. Also, the maximum level of androsterone and 11$\beta$-hydroxy androsterone, which were endogenous steroids, were reached 4.1 h after the oral administration of adrenosterone.

• 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.

• 한국식품위생안전성학회지
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• 제33권1호
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• pp.58-64
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• 2018

본 연구는 소의 가식부위(근육, 신장, 간장, 지방) 중에서 세팔렉신을 효과적으로 정량분석하기 위한 LC-MS/MS법을 확립하고 이를 검증하기 위해 수행되었다. 확립된 LC-MS/MS에 대해 특이성, 검출한계, 정량한계, 정확도 및 정밀도에 대한 검증을 통하여 유효성을 확인하였다. 표준 용액을 이용하여 검량성을 작성한 결과, $r^2$ > 0.999 이상의 직선성을 나타내었으며, 세팔렉신에 대한 검출한계와 정량한계는 각각 2~10과 $6{\sim}30{\mu}g/kg$으로 나타났다. 또한, 회수율은 83.9~106.8%로 나타났으며, 상대표준편차는 2.3~14.8%로 나타나 정확성이 우수하였다. 이는 식품의약품안전처의 잔류동물용의약품 분석법에서 제시한 기준에 모두 적합한 수준이었다. 따라서 본 연구를 통해 개발된 LC-MS/MS법은 향후 소의 가식부위 중 세팔렉신을 분석하는데 효과적으로 활용될 수 있을 것으로 사료된다.

• 한국식품위생안전성학회지
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• 제32권5호
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• pp.418-423
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• 2017

본 연구는 우유 중에서 덱사메타손을 효과적으로 정량분석하기 위한 LC-MS/MS법을 확립하고 이를 검증하기 위해 수행되었다. 확립된 LC-MS/MS에 대해 특이성, 검출한계, 정량한계, 정확도 및 정밀도에 대한 검증을 통하여 유효성을 확인하였다. 표준용액을 이용하여 검량성을 작성한 결과, $r^2$ > 0.999 이상의 직선성을 확인하였고, 덱사메타손에 대한 검출한계와 정량한계는 각각 0.15와 0.5 ng/mL이었다. 또한, 회수율은 98.9-109.6%로 나타났으며, 상대표준편차는 1.7-4.4%로 나타나 정확성이 우수하였으며, 이는 식품의약품안전처의 잔류동물용의약품 분석법에서 제시한 기준에 모두 적합한 수준이었다. 따라서 본 연구를 통해 개발된 LC-MS/MS법은 향후 우유 중 덱사메타손을 분석하는데 효과적으로 활용될 수 있을 것으로 사료된다.

• 대한화학회지
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• 제54권5호
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• pp.523-532
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• 2010

제안된 방법은 국제표준(IS)인 Entacapone-d10(EAD10)을 사용하여 체외에서 Entacapon(EA)의 정량화를 위한 간단하고, 감도가 좋고, 명확한 액체 크로마토그래피-직렬 질량 분석법(LC-ESI-MS/MS)이다. 크로마토그래피 분리는 Zorbax SB-C18에서 수행되었고, $2.1{\times}50\;mm$, $5\;{\mu}m$ 컬럼과 10 mM Ammonium formate (pH 3.0)로 구성된 이동상에서 수행되었다: 0.7 mL/min 유속의 아세토나이트릴(60:40 v/v)은 액체-액체 추출을 따른다. EA와 EAD10은 다중 반응 탐색법(MRM)에서 수소부가물을 가지고 상대적으로 포지티브 모드인 m/z $306.1{\rightarrow}233.1$과 $316.3{\rightarrow}233.0$에서 수소부과물을 가지고 측정되었다. 그 방법은 상관계수($r^2$) 0.993 이상을 갖는 1.00 - 2000.00 ng/mL의 선형 농도 범위 이상으로 입증되었다. 하루 중과 하루 이내에 3.60에서 7.30과 4.20에서 5.50% 이내의 정밀성과 97.30에서 104.20과 98.30에서 105.80% 이내의 정확도는 EA를 위해 입증되었다. 이러한 방법은 건강한 인도인 자원자들의 생물학적 동등성 연구에서 성공적으로 적용되었다.

• 분석과학
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• 제20권2호
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• pp.138-146
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• 2007

본 연구에서는 비글견 혈장 중의 파록세틴을 액체상추출법(LLE)으로 전처리하고 액체크로마토그래피-탠덤질량분석기(LC-MS/MS)로 신속하게 분석하는 방법을 개발하였다. 파록세틴과 내부표준물질로 사용한 플루오세틴을 TBME(tert-butyl methyl ether)로 추출하고 상층액을 취하여 건조시킨 후, 이동상 $100{\mu}L$로 재분산하여 LC-MS/MS에 주입하였다. HPLC 분석조건으로 Capcell Pak UG120($2.0{\times}150mm$, $5{\mu}m$) 컬럼을 사용하였으며, 이동상은 50% 아세토니트릴(pH 3, formic acid로 조정) 용액을 사용하였고, 유량은 0.2 mL/min으로 하였다. MS/MS의 SRM(selective reaction monitoring) 방법으로 파록세틴과 플루오세틴의 선구 이온, 생성 이온을 각각 m/z $330{\rightarrow}192$, m/z $310{\rightarrow}148$로 분석한 결과 0.02~5 ng/mL의 농도범위에서 상관계수($R^2$) 0.9993으로 좋은 직선성을 나타내었다. 또한 정량한계는 0.02 ng/mL이며, 정밀성은 일내 및 일간 변동계수가 7.67% 이하이고, 정확도는 92.96~102.99%로 비글견 혈장 중의 파록세틴의 약물동력학 연구에 이용될 수 있는 충분한 감도와 특이성, 직선성, 정밀성 및 정확성을 갖고 있음을 확인하였다.

• 한국식품과학회지
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• 제36권4호
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• pp.643-647
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• 2004

땅콩껍질에 함유된 항미생물 활성물질의 탐색을 위해 땅콩껍질을 MeOH로 추출하고 이 MeOH 추출물을 용매분획하여 EtOAc 중성획분을 얻었다. 이 획분에 함유된 항미생물 활성물질을 silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, ODS column chromatography로 정제한 다음 HPLC를 이용하여 1종의 화합물을 단리하였다. $^1H-NMR$, MS 및 NOESY 분석에 의해 땅콩껍질로부터 분리된 항미생물 활성물질은 pratensein으로 동정되었다.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.838-845
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• 2011

The present work describes the identification, purification, and characterization of bile salt hydrolase (BSH) from Bifidobacterium animalis subsp. lactis. The enzyme was purified to electrophoretic homogeneity by hydrophobic chromatography, ion-exchange chromatography and ultrafiltration. SDS-PAGE analysis of putative BSH and gel filtration revealed that the analyzed protein is presumably a tetramer composed of four monomers each of about 35 kDa. The purified enzyme was analyzed by liquid chromatography coupled to LTQ FT ICR mass spectrometry and unambiguously identified as a bile salt hydrolase from B. animalis. The isoelectric point of the studied protein was estimated to be around pH 4.9. The pH optimum of the purified BSH is between 4.7 to 6.5, and the temperature optimum is around 50oC. The BSH of B. animalis could deconjugate all tested bile salts, with clear preference for glycine-conjugated bile salts over taurine-conjugated forms. Genetic analysis of the bsh showed high similarity to the previously sequenced bsh gene from B. animalis and confirmed the usefulness of bile salt hydrolase as a genetic marker for B. animalis identification.

• 한국수산과학회지
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• 제47권6호
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• pp.882-887
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• 2014

We studied oocyte steroidogenesis in blacktip grouper Epinephelus fasciatus ovarian follicles during vitellogenesis. Vitellogenic oocytes with average diameters of 0.45, 0.48 and 0.50 mm were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone as a precursor. The steroid metabolites were analyzed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC/MS). The major metabolites in the vitellogenic oocytes were androstenedione ($A_4$), testosterone (T), estradiol-$17{\beta}$ ($E_2$), and estrone ($E_1$). The metabolites of androgen ($A_4$ and T) were higher in the 0.50-mm oocytes than in the 0.45- and 0.48-mm oocytes, while the estrogen metabolites (E2 and E1) were lower in the 0.50-mm oocytes. These results suggest that 0.50-mm oocytes are fully vitellogenic following initiation of the maturation process.

• 보존과학회지
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• 제35권1호
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• pp.51-60
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• 2019

This paper provides quantitative data that describes the evolution of the air quality in the Whale and Sea Museum, located in the Iwate prefecture, collected after the 2011 Great East Japan Earthquake and tsunami. The museum was damaged significantly by the disaster, and restoration works continued for over six years. The air quality in the temporary storage facility and museum was monitored during the rehabilitation process. Evaluation of air quality is carried out by gas chromatography- mass spectrometry, ion chromatography and high-performance liquid chromatography. The results showed that the characteristics of the chemical components differed depending on the measurement locations inside the building. The museum atmosphere tended to be alkaline as the airtightness increased because of the maintenance works at the entrance. It was also determined that it was necessary to study the intake/exhaust routes and to clean them according to the contamination degree. In Japan, there are recommended museum air quality standards for acetic acid, formic acid, alkali, and aldehydes. The results indicated that these standards should not be used as a reference for damaged museums. Furthermore, at the temporary storage facilities for to store the collections during the rehabilitation of the museum, solvents such as ethyl benzene, toluene, and xylene are initially abundant, although they can be reduced by ventilation, while other components such as 2E1H was confirmed in this case are likely to remain.