The use of stable isotopes in biosynthetic studies

Vederas, John C.

doi:10.1039/np9870400277

Cited by 89 publications

(79 citation statements)

References 131 publications

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“…C-17, and C-18 in its 2H-NMR spectrum. The ratio (0.7: I : 0.4: 3) of integrals essentially reflected that of the labelled prosolanapyrone II (16). These results demonstrate intact incorporation of intermediates 15 and 16.…”

supporting

confidence: 60%

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Biosynthesis of Phytotoxins fromAlternaria solani

Ichihara

Oikawa

1997

Bioscience, Biotechnology, and Biochemistry

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supporting

confidence: 60%

“…Solanapyrone A (8) derived from [2H5]-15 had two signals due to deuterium at C-I7 and C-18 in its 2H-NMR spectrum. Furthermore, the product 8 derived from the deuterium-labelled 16 showed duterium resonances at C-2, C-3. C-17, and C-18 in its 2H-NMR spectrum.…”

mentioning

confidence: 99%

Biosynthesis of Phytotoxins fromAlternaria solani

Ichihara

Oikawa

1997

Bioscience, Biotechnology, and Biochemistry

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“…A complete quantitative analysis is hindered in this case by the large contributions to these second-stage MS spectra from other ethane isotopologues. On the other hand, clear semi-quantitative conclusions can be reached by simple inspection of the cracking patterns, in particular because of the clear differences in the 24 -36 Da region between the spectra of CD 2 HCDH 2 (d 3,s ) and CD 3 CH 3 (d 3,a ). Notice, for instance, the predominance of the peaks at 30 and 31 Da in the asymmetric and symmetric cases, respectively, and also their corresponding intense peaks at 15 and 18 (CH 3 ϩ and CD 3 ϩ ) versus 16 and 17 (CDH 2 ϩ and CD 2 H ϩ ) Da.…”

Section: Resultsmentioning

confidence: 99%

“…Notice, for instance, the predominance of the peaks at 30 and 31 Da in the asymmetric and symmetric cases, respectively, and also their corresponding intense peaks at 15 and 18 (CH 3 ϩ and CD 3 ϩ ) versus 16 and 17 (CDH 2 ϩ and CD 2 H ϩ ) Da. The second-stage MS/CID-MS spectra from both mixtures show, after correcting for the contributions from the other isotopologs (ethane-d 4 and -d 5 , leading to the traces labeled "corrected"), strong peaks at 16, 17, and 31 Da, and negligible remaining intensities ascribable to asymmetric ethane-d 3 . The analysis of the components due to four H™D exchanges is even more uncertain, but also points to a predominance of symmetrically substituted isotopologues.…”

Section: Resultsmentioning

confidence: 99%

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Regiospecificity in deuterium labeling determined by mass spectrometry

Loaiza

Zaera

2004

J. Am. Soc. Mass Spectrom.

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Several mass spectrometry methods were explored to determine the regiospecificity of deuterium substitutions in hydrocarbon mixtures. The case investigated in this work was that of ethane mixtures obtained by catalytic H™D exchange between either C 2 H 6 and D 2 or C 2 D 6 and H 2 over platinum surfaces. A total of ten isotopologs are possible, and were indeed detected in all cases. Deconvolution of low-resolution mass spectra was found sufficient to determine the composition of the gas mixtures in terms of the total number of deuterium substitutions, but not to identify symmetric versus asymmetric substitutions in the C 2 D 2 H 4 , C 2 D 3 H 3 , and C 2 D 4 H 2 products. High-resolution mass spectrometry allowed the separation of the intensities due to C 2 X 4 ϩ fragments from those from molecular C 2 X 6 ϩ signals (X ϭ H or D), and with that for a more accurate determination of the composition of the mixtures. Relative probabilities were determined for the symmetric versus asymmetric removal of X 2 from C 2 X 6 ϩ ions and for isotope scrambling in the mass spectrometer, and with that information fairly good cracking patterns were then calculated for the C 2 X 4 ϩ fragments produced by each individual pure C 2 X 6 isotopologue. However, total deconvolution of all ten components in the ethane mixtures obtained by H™D exchange catalysis was beyond the experimental accuracy of the measurements. Tandem mass spectrometry/collision-induced decomposition mass spectrometry (MS/CID-MS) proved more useful for this task. In particular, it was possible to determine the proportion of symmetric versus asymmetric double H™D exchange in samples for which the total ethane-d 2 (in the case of C 2 H 6 ϩ D 2 ) or ethane-d 4 (with C 2 D 6 ϩ H 2 ) amounted to only ϳ3% on the ethane mix. A comparison with other analytical methods, NMR in particular, is provided. (J Am Soc Mass Spectrom 2004, 15, 1366 -1373

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Isotope effects on chemical shifts of proteins and peptides

Hansen

2000

Magn. Reson. Chem.

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The use of stable isotopes in biosynthetic studies

Cited by 89 publications

References 131 publications

Biosynthesis of Phytotoxins fromAlternaria solani

Biosynthesis of Phytotoxins fromAlternaria solani

Regiospecificity in deuterium labeling determined by mass spectrometry

Isotope effects on chemical shifts of proteins and peptides

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