Carbon-13 NMR protonation shifts of amines, carboxylic acids and amino acids

Batchelor, John G.; Feeney, J.; Roberts, Gordon C. K.

doi:10.1016/0022-2364(75)90146-8

Cited by 56 publications

(14 citation statements)

References 21 publications

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“…Upfield protonation shifts of aliphatic carboxylic acids for the α, β, γ, and δ carbons are typically 3-4, 1.5, 0.6, and 0.2 ppm, respectively [69]. An anomalous trend has been recorded for α-amino acids: upon protonation of the amino group, larger 13 C shifts are detected for the carboxylic and β-carbons than for the amino-bearing α-carbon [76,77,78,79]. This β-effect could be in part rationalized in terms of the linear electric field shift (LEFS) theory [76,77].…”

Section: Nmr Titrationsmentioning

confidence: 96%

“…An anomalous trend has been recorded for α-amino acids: upon protonation of the amino group, larger 13 C shifts are detected for the carboxylic and β-carbons than for the amino-bearing α-carbon [76,77,78,79]. This β-effect could be in part rationalized in terms of the linear electric field shift (LEFS) theory [76,77]. Moreover, it has also been stated that for amino acids and derivatives protonation of (up to 5 bonds) remote sites can influence the 13 C chemical shift [80,81], although not monotonously.…”

Section: Nmr Titrationsmentioning

confidence: 97%

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Determination of microscopic acid?base parameters from NMR?pH titrations

Szakács

Kraszni

Noszál

2004

Analytical and Bioanalytical Chemistry

106

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The theory and practice of proton microspeciation based on NMR-pH titrations are surveyed. Principles of bi-, tri-, tetra-, and n-protic microequilibrium systems are discussed. Evaluation methods are exemplified by case studies on bi- and tetraprotic biomolecules. Selection criteria and properties of 'reporter' NMR nuclei are described. Literature data on complete microspeciations of small ligands and site-specific basicity characterizations of peptides and proteins are critically reviewed.

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Section: Nmr Titrationsmentioning

confidence: 96%

Section: Nmr Titrationsmentioning

confidence: 97%

Determination of microscopic acid?base parameters from NMR?pH titrations

Szakács

Kraszni

Noszál

2004

Analytical and Bioanalytical Chemistry

106

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“…Protonation of either the amino or carboxylate group generally favors an upfield shift of the nearby carbons, with of the β-carbon usually experiencing larger up-field than the α-carbon [16-18]. The pKa values of glutamate carboxylates are 2.19 and 4.25 while the protonation constants for dicarboxylic acids without an amino group are typically pKa1 ∼ 3 and pKa2 ∼ 5 to 7 [17,18].…”

mentioning

confidence: 99%

Conditions for 13C NMR detection of 2-hydroxyglutarate in tissue extracts from isocitrate dehydrogenase-mutated gliomas

Pichumani

Mashimo

Baek

et al. 2015

Analytical Biochemistry

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13C NMR spectroscopy of extracts from patient tumor samples provides rich information about metabolism. However, in IDH-mutant gliomas 13C labeling is obscured in glutamate and glutamine by the oncometabolite, 2-hydroxyglutaric acid (2HG), prompting development of a simple method to resolve the metabolites. J-coupled multiplets in 2HG were similar to glutamate and glutamine and could be clearly resolved at pH 6. A cryogenically-cooled 13C probe but not J-resolved heteronuclear single quantum coherence spectroscopy significantly improved detection of 2HG. These methods enable the monitoring of 13C-13C spin-spin couplings in 2HG expressing IDH mutant gliomas.

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“…This immediately excluded spermine and spermidine, detected earlier in seminal fluid, 20 and also putrescine, since a more complex 1 H NMR spectrum was expected as a consequence of its [(AX) 2 ] 2 spin system and lack of a C,H chemical shift 'crossover' effect (Table 1). Although we do not understand this 'crossover' effect in detail we believe that the main contribution arises from the electric fields 21 of the charged groups on the 13 C chemical shifts. In the following this effect was very useful for the elimination of a large number of compounds, including ␤-alanine (Table 1).…”

Section: Hypotaurinementioning

confidence: 92%