Thin‐Layer Chromatography

Meyers, Caren L. Freel; Meyers, David J.

doi:10.1002/0471142700.nca03ds34

Cited by 60 publications

(110 citation statements)

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“…The water-soluble metabolites were separated and identified via comparison of the retention factor (R f ) with those of the cold standards. The R f is defined as the ratio of moving distance of the compound to the moving distance of the solvent from the origin [18]. The plate was eluted to a distance of 15 cm with an elapsed time of ~3 h. The plate was then air-dried and visualized using short wave UV light (handheld lamp), and sample lanes were scanned using the Bioscan AR 2000 (Bioscan Inc., Washington, DC, USA) to quantify the incorporation of radioactivity in each metabolite.…”

Section: Methodsmentioning

confidence: 99%

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

et al. 2013

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Purpose Radiolabeled methionine (Met) promises to be useful in the positron emission tomography (PET) imaging of hepatocellular carcinoma (HCC). However, its metabolic routes in HCC have not yet been fully understood. In this study, the metabolic pathway(s) of radiolabeled Met in HCC were investigated. Procedures To simulate the rapid blood clearance of radiolabeled Met, pulse–chase experiments were conducted. L-[methyl-3H]-Met or L-[1-14C]-Met was pulsed over control or cycloheximide- treated WCH17 cells and rat hepatocytes for 5 min and chased with cold media. The water-soluble, lipid-soluble, DNA, RNA, and protein phases were subsequently extracted and measured from the acid-precipitable and acid-soluble fractions of whole cells. The radioactive metabolites Met, S- adenosylmethionine (SAM), S-adenosylhomocysteine, Met sulfoxide, and Met sulfone were further separated by radio thin layer chromatography. Results (1) The uptake of L-[methyl-3H]-Met in both cell types was higher than that of L-[1-14C]-Met. In rat hepatocytes, the uptake of L-[methyl-3H]-Met was significantly higher than that of L-[1-14C]-Met, which may contribute to its physiologic accumulation in surrounding hepatic tissues seen in PET imaging of HCC using L-[methyl-11C]-Met. Compared to rat hepatocytes, WCH17 cells had significantly higher uptake of both radiotracers. (2) For L-[methyl-3H]-Met, the major intracellular uptake was found mostly in the protein phase and, to a lesser degree, in the phosphatidylethanolamine (PE) methylation pathway, which is fairly stabilized within the 55-min chase period (the main metabolites were SAM, Met, Met sulfoxide, and Met sulfone). In contrast, the uptake of Met in rat hepatocytes mainly points to phosphatidylcholine (PC) synthesis through the PE methylation pathway (the main metabolite was PC). (3) Both cell types incorporated L-[1-14C]-Met predominantly into protein synthesis. (4) Finally, when the protein synthesis pathway was inhibited, the incorporation of SAM derived from L-[methyl-3H]-Met to lipid class (PC was the main metabolite) occurred at a reduced rate in WCH17 cells, suggesting that the route may be impaired in HCC. Conclusions This study demonstrated that different metabolic pathways of radiolabeled Met exist between HCC and surrounding hepatic tissue and contribute to the patterns of increased uptake of radiolabeled Met in HCC.

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Section: Methodsmentioning

confidence: 99%

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

et al. 2013

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“…Monitor progress by TLC (Meyers et al, 2008) and disappearance of starting material using 10% methanol in dichloromethane. Product R f = 0.94.…”

Section: Basic Protocolmentioning

confidence: 99%

Synthesis of Fluorescence Turn‐On DNA Hybridization Probe Using the ^DEAtC 2′‐Deoxycytidine Analog

Turner

Anderson

Samaan

et al. 2018

CP Nucleic Acid Chemistry

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DEAtC is a tricyclic 2’-deoxycytidine analogue that can be incorporated into oligonucleotides by solid-phase synthesis and that exhibits a large fluorescence enhancement when correctly base-paired with guanine base in a DNA–DNA duplex. The synthesis of DEAtC begins with 5-amino-2-methylbenzothiazole and provides the DEAtC nucleobase analogue over four synthetic steps. This nucleobase analogue is then silylated using BSA and conjugated to Hoffer’s chlorosugar to provide the protected DEAtC nucleoside in good yield. Following protective group removal and chromatographic isolation of the β-anomer, dimethoxytritylation and phosphoramidite synthesis offered the monomer for solid-phase DNA synthesis. Solid-phase DNA synthesis conditions using extended coupling of the DEAtC amidite and a short deprotection time are used to maximize efficiency. By following the protocol described in this unit, the DEAtC fluorescent probe can be synthesized and incorporated into any desired synthetic DNA oligonucleotide.

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“…18. Characterize the product by TLC (APPENDIX 3D; Meyers & Meyers, 2008) and 1 H NMR. (2,3-O-Isopropylidene-5-O-tert-butyldiphenylsilyl-4-seleno-β-D-ribofranosyl)…”

Section: -(23-o-isopropylidene-5-o-tert-butyldiphenylsilyl-4-selenomentioning

confidence: 99%

Synthesis of 4′‐Selenoribonucleosides, the Building Blocks of 4′‐SelenoRNA, Using a Hypervalent Iodine

Saito–Tarashima

Ota

Minakawa

2017

CP Nucleic Acid Chemistry

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Herein is described a detailed protocol for the synthesis of 4'-selenoribonucleoside derivatives that involves the use of a hypervalent iodine species. These derivatives are versatile units for the preparation of 4'-selenoRNA. Large-scale synthesis of a 4-selenosugar starting from D-ribose is achieved in eight steps, including a final chromatographic purification. The resulting 4-selenosugar is then subjected to the one-pot Pummerer-like reaction using hypervalent iodine in the presence of silylated nucleobases. The reaction with silylated uracil affords the desired 4'-selenouridine derivatives with excellent β-selectivity and in good yield. Conversely, when purine nucleobases are used in the Pummerer-like reaction, N7 4'-selenoribonucleoside isomers are obtained alongside the desired N9 isomers. However, the undesired N7 isomers can be converted to the desired N9 ones under acidic conditions. © 2017 by John Wiley & Sons, Inc.

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Thin‐Layer Chromatography

Cited by 60 publications

References 1 publication

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

Synthesis of Fluorescence Turn‐On DNA Hybridization Probe Using the ^DEAtC 2′‐Deoxycytidine Analog

Synthesis of 4′‐Selenoribonucleosides, the Building Blocks of 4′‐SelenoRNA, Using a Hypervalent Iodine

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Thin‐Layer Chromatography

Cited by 60 publications

References 1 publication

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

Synthesis of Fluorescence Turn‐On DNA Hybridization Probe Using the DEAtC 2′‐Deoxycytidine Analog

Synthesis of 4′‐Selenoribonucleosides, the Building Blocks of 4′‐SelenoRNA, Using a Hypervalent Iodine

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Synthesis of Fluorescence Turn‐On DNA Hybridization Probe Using the ^DEAtC 2′‐Deoxycytidine Analog