• Fisheries and Aquatic Sciences
• /
• 제15권1호
• /
• pp.15-19
• /
• 2012

A new cyclic peptide (six-membered amino acid), gamakamide-E (L-Leu-L-Met (SO)-L-Me-Phe-L-Leu-D-Lys-L-Phe), was isolated as a strongly bitter tasting compound from cultured oysters, Crassostrea gigas. The molecular formula of $C_{43}H_{61}N_7O_8S$ was deduced from high resolution fast atom bombardment mass spectrometry (HR FAB-MS) ($[M+H]^+$ m/z 836.4356 ${\Delta}$= -2.4 mmu). Its unique structure including a hydantoin structure was firstly elucidated by nuclear magnetic resonance (NMR) analysis. Stereochemistries of constituent amino acids were determined by chiral high performanced liquid chromatography analysis of natural and synthesized peptides.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제37권2호
• /
• pp.43-48
• /
• 2018

Mulberry fruit is a new income product in Korea sericulture due to the increase of fruit consumption. However, flavonoids of Korean mulberry cultivar for fruit production did not reported yet. In this study, the typical mulberry cultivar, 'Daeshim' was analyzed using ultrahigh performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS) technique for flavonoids analysis. Nine flavonoids were isolated and analyzed from Daeshim using UPLC-DAD-QTOF/MS chromatogram. According to quantitative analysis, rutin (66.1 mg/100g DW) and quercetin 3-O-(6"-O-malonyl) glucoside (26.7 mg/100g DW) were abundant in mulberry fruit. Our results might be used as basic information for mulberry consumption.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.394.2-394.2
• /
• 2002

A sensitive and selective reversed-phase LC-ESI-MS method to quantitate pseudoephedrine in human plasma was developed and validated. Phenacetin was used as an internal standard. Samples were prepared simply by acetonitrile precipitation without an evaporation step. Chromatographic separation was achieved on a XTerra MS C18 column ($150{times}2.1$ mm I.D.. 3.5 $\mu\textrm{m}$ particles). using gradient elution with 0.5% (v/v) trifluoroacetic acid (TFA) in water and 0.5% (v/v) TFA in methanol at a flow-rate of 0.1 ml/min. (omitted)

• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
• /
• pp.213.1-213.1
• /
• 2003

Sphingolipids and their metabolites are highly bioactive molecules that affect various cellular functions including differentiation, cellular senescence, apoptosis, and proliferation when added exogenously, or elevated intracellularly by turnover of complex sphingolipids or synthesis from de novo pathway. We are investigating the relationship of sphingolipids cycle in apoptosis early events. A new column liquid chromatography- tandem mass spectrometry (LC/MS/MS) in combination with multiple reaction monitoring (MRM) method was developed for the rapid, simultaneous and quantitative determination of unambiguous detecting sphingolipids in cells. (omitted)

• Biomolecules & Therapeutics
• /
• 제31권5호
• /
• pp.566-572
• /
• 2023

A chiral derivatization strategy with phenylglycine methyl ester (PGME) was employed to develop a straightforward method to determine the absolute configurations of N,N-dimethyl amino acids. The PGME derivatives were analyzed using liquid chromatography-mass spectrometry to identify the absolute configurations of various N,N-dimethyl amino acids based on their elution time and order. The established method was applied to assign the absolute configuration of the N,N-dimethyl phenylalanine in sanjoinine A (4), a cyclopeptide alkaloid isolated from Zizyphi Spinosi Semen widely used as herbal medicine for insomnia. Sanjoinine A displayed production of nitric oxide (NO) in LPS-activated RAW 264.7 cells.

• 분석과학
• /
• 제36권1호
• /
• pp.12-21
• /
• 2023

Protein glycation is vital to aging and disease. However, glycated proteins are low-abundant in plasma, rendering them difficult to identify using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Many studies have analyzed glycated peptides with high reproducibility. Here, glycated peptides in human serum were analyzed by LC-MS/MS using data-dependent acquisition (DDA) and parallel reaction monitoring (PRM). Boronic acid (BA) enrichment of in vitro glycated human serum peptides was performed. BA enrichment identified the most glycated peptides, and the glycated peptides of the more diversified proteins, excluding albumin, were analyzed. In PRM, glycated albumin PSMs were the most common, and this method exhibited the best reproducibility. The results of this study could help compare methods for identifying glycation-related biomarkers.

• 분석과학
• /
• 제19권1호
• /
• pp.103-106
• /
• 2006

A 35-year-old Perubian who suffered from grand mal seizures died in the aircraft on his way from the United States to Hongkong via Incheon international airport of Korea. While performing the autopsy, 115 packs made with double layer of transparent film and black plastic bag containing cocaine were found in the ileum and large intestine. Among of them, 3 packs were ruptured. To determine the concentration of cocaine and its metabolites, blood, urine, bile, liver, spleen, heart, kidney, brain and gastric contents were taken and toxicological analysis was performed. Gas chromatography/mass spectrometry (GC/MS) following liquid-phase extraction using chloroform:isopropanol (=9:1) and derivatization with bis(trimethylsilyl)-trifluoroacetamide (contains 1% trimethylchlorosilane) was performed. High levels of cocaine, benzoylecgonine (BE) and ecgonine methylester (EME) were found in the postmortem blood (0.96, 3.09 and $5.59{\mu}g/mL$) and urine (32.85, 145.35 and $53.17{\mu}g/mL$), respectively. Cocaine and its metabolites were also detected in all other biological specimen.

• Journal of Microbiology and Biotechnology
• /
• 제27권6호
• /
• pp.1090-1097
• /
• 2017

Rhus verniciflua Stokes (RVS), an herbal medicine found in East Asia, was extracted and further fractionated to investigate its antioxidant capacity and neuroprotective effects. The RVS ethyl acetate (EtOAc) fraction had the highest level of total phenolics and antioxidant capacity among all solvent fractions tested. Pretreatment of PC-12 cells with the EtOAc fraction effectively attenuated $H_2O_2$-induced oxidative damage. Furthermore, the EtOAc fraction significantly attenuated caspase-3 activity, resulting in inhibition of $H_2O_2$-induced apoptosis. We identified and quantified fustin, sulfuretin, and butein in the EtOAc fraction using accurate mass quadrupole time-of-flight mass spectrometry and reversed-phase high-performance liquid chromatography. The intracellular antioxidant capacity and superoxide dismutase (SOD) activity were significantly increased in PC-12 cells treated with the EtOAc fraction and with individual flavonoids. When cells were pretreated with the EtOAc fraction or individual flavonoids and then co-incubated with diethyldithiocarbamic acid (an inhibitor of SOD activity), cell viability against $H_2O_2$-induced oxidative stress was attenuated. These results suggest that the RVS EtOAc fraction and its flavonoid constituents protect PC-12 cells against $H_2O_2$-induced neurotoxicity through their antioxidant properties.

• Journal of Microbiology and Biotechnology
• /
• 제17권2호
• /
• pp.207-217
• /
• 2007

The Saccharomyces0 cerevisiae KNU5377 strain, which was isolated from spoilage in nature, has the ability to convert biomass to alcohol at high temperatures and it can resist against various stresses [18, 19]. In order to understand the defense mechanisms of the KNU5377 strain under menadione (MD) as oxidative stress, we used several techniques for study: peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) followed by two-dimensional (2D) gel electrophoresis, liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and surface-enhanced laser desorption ionization-time of flight (SELDI-TOF) technology. Among the 35 proteins identified by MALDI-TOF MS, 19 proteins including Sod1p, Sod2p, Tsa1p, and Ahp1p were induced under stress condition, while 16 proteins were augmented under normal condition. In particular, five proteins, Sod1p, Sod2p, Ahp1p, Rib3p, Yaf9p, and Mnt1p, were induced in only stressed cells. By LC-ESI-MS/MS analysis, 37 proteins were identified in normal cells and 49 proteins were confirmed in the stressed cells. Among the identified proteins, 32 proteins were found in both cells. Five proteins including Yel047cp and Met6p were only upregulated in the normal cells, whereas 17 proteins including Abp1P and Sam1p were elevated in the stressed cells. It was interesting that highly hypothetical proteins such as Ynl281wp, Ygr279cp, Ypl273wp, Ykl133cp, and Ykr074wp were only expressed in the stressed cells. SELDI-TOF analysis using the SAX2 and WCX2 chips showed that highly multiple-specific protein patterns were reproducibly detected in ranges from 2.9 to 27.0 kDa both under normal and stress conditions. Therefore, induction of antioxidant proteins, hypothetical proteins, and low molecular weight proteins were revealed by different proteomic techniques. These results suggest that comparative analyses using proteomics might contribute to elucidate the defense mechanisms of KNU5377 under MD stress.

• 분석과학
• /
• 제21권5호
• /
• pp.424-431
• /
• 2008

스트렙토마이신은 아미노글리코사이드계 항생제중의 하나로써 가축, 가금류의 질병 치료와 예방에 널리 사용되고 있다. 국내에서는 양봉용으로는 허가되어 있지 않지만 일부 국가에서는 유럽형 부저병과 같은 세균성 벌꿀 질병의 치료에 사용되는 것으로 알려져 있다. LC-MS/MS를 이용하여 벌꿀 중에 잔류하는 스트렙토마이신(streptomycin)을 분석하는 방법을 확립하였다. 확립된 분석법은 재현성과 정밀성을 높이고 미량까지 검출할 수 있도록 회수율을 높이기 위하여 정제 및 추출과정을 최적화 하였으며, 효과적인 분석을 위해서 액체 크로마토그래피(HPLC) 와 텐뎀 질량분석법(tandem mass spectrometry)의 조건들을 최적화하였다. 확립된 방법은 5.0~50.0 ug/kg 농도에서 5.5~14%인 정밀성(RSD)을 나타내었으며, bias로써 -10.0~8.0%의 정확도를 나타내었다. 한편, 스트렙토마이신을 벌꿀 공 시료에 10.0 ug/kg의 농도로 소량첨가한 후 얻은 회수율은 74%이었고, 정량한계(LOQ)는 0.75 ug/kg이었다. 확립된 벌꿀 중 스트렙토마이신 분석법을 이용하여 실제 벌꿀시료에 적용한 결과 몇몇 시료에서 소량의 스트렙토마이신이 검출되었다.