Gas-phase acid-base properties of homocysteine, homoserine, 5-mercaptonorvaline, and 5-hydroxynorvaline from the extended kinetic method

Muetterties, Corbin; Janiga, Ashley; Huynh, Kathy T.; Pisano, M. Grace; Tripp, Valerie T.; Young, Douglas D.; Poutsma, John C.

doi:10.1016/j.ijms.2014.06.010

Cited by 9 publications

(7 citation statements)

References 80 publications

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“…). This confirms that the most acidic group of cysteine is likely the thiol group as it has been shown recently by Muetterties et al in their study on homocysteine . The second most stable complex, DMT‐η 2 ‐Z‐O , S‐2 , also involves the most acidic site of cysteine and is located 31 kJ mol −1 above the global minimum.…”

Section: Resultssupporting

confidence: 86%

Gas‐phase interactions of organotin compounds with cysteine

et al. 2016

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The gas-phase interactions of cysteine with di-organotin and tri-organotin compounds have been studied by mass spectrometry experiments and quantum calculations. Positive-ion electrospray spectra show that the interaction of di- and tri-organotins with cysteine results in the formation of [(R) Sn(Cys-H)] and [(R) Sn(Cys)] ions, respectively. MS/MS spectra of [(R) Sn(Cys-H)] complexes are characterized by numerous fragmentation processes, notably associated with elimination of NH and (C,H ,O ). Several dissociation routes are characteristic of each given organic species. Upon collision, both the [(R) Sn(Gly)] and [(R) Sn(Cys)] complexes are associated with elimination of the intact amino acid, leading to the formation of [(R) Sn] cation. But for the latter complex, two additional fragmentation processes are observed, associated with the elimination of NH and C H O S. Calculations indicate that the interaction between organotins and cysteine is predominantly electrostatic but also exhibits a considerable covalent character, which is slightly more pronounced in tri-organotin complexes. A preferred bidentate interaction of the type -η -S-NH , with sulfur and the amino group, is observed. As for the [(R) Sn(Cys)] complexes, their stability is due to the combination of the hydrogen bond taking place between the amino group and the sulfur lone pair and the interaction between the carboxylic oxygen atom and the metal. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Resultssupporting

confidence: 86%

Gas‐phase interactions of organotin compounds with cysteine

et al. 2016

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“…As mentioned earlier, the differences in acidities for the aliphatic amino acids are much smaller than the differences in PA. All of the aliphatic amino acids have acidities within a range of 15 kJ/mol (DH acid (Gly) = 1434 kJ/mol), DH acid (Ala) = 1430 kJ/mol, DH acid (Val) = 1431 kJ/mol, DH acid (Leu) = 1419 kJ/mol, and DH acid (Ile) = 1423 kJ/mol) [28]. The acidities of 1-4 are all within this range and these results add to the growing body of literature on the acidities of unusual amino acids in which the NPAA-analogs have the same acidity as their PAA counterparts [29,40]. Amino acids 1-4 are related to the cycloalkanecarboxylic acids by the addition of an NH 2 group at the a-carbon.…”

Section: Comparisons and Trendssupporting

confidence: 52%

“…To date we have measured the PA 9 and GA 29 of proline and its 4-and 6-membered ring analogs, the PA 10 and GA 29 of lysine, and its lower homologs, ornithine, 2,4-diaminobutanoic acid, and 2,3-diaminoproanoic acid, the PA and GA of longer homologs of serine and cysteine [40], and the PA of oxy-analogs of arginine and ornithine [12]. For most of these systems, we find a direct correlation between PA and the number of carbon atoms in the side chain.…”

Section: Introductionmentioning

confidence: 99%

Gas-phase acid-base properties of 1-aminocycloalkane-1-carboxylic acids from the extended kinetic method

Muetterties

Touzani

Hardee

et al. 2015

International Journal of Mass Spectrometry

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“…There are several factors that affect PAs, including hydrogen‐bonding interactions, isotropic polarizabilities, and electronegativities for molecules that have undergone chemical modifications. Molecules with high PAs tend to have extensive intramolecular hydrogen bonds and high polarizabilities as the proton is more tightly bound, whereas high electronegativity of halogens results in a decreased PA due to the electron density being pulled away from the proton . It is also suggested that there is a relationship between the proton‐molecule distance in the protonated dimer precursor used for PA determination and the PA value.…”

Section: Introductionmentioning

confidence: 99%

Extended kinetic method study of the effect of ortho‐, meta‐, and para‐chlorination on the proton affinity of phenylalanine with full entropy analysis

Shin

2019

J of Physical Organic Chem

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Extended kinetic method study of the effect of ortho-, meta-, and para-chlorination on the proton affinity of phenylalanine with full entropy analysis Joong-Won ShinAbstract Absolute proton affinities (PAs) of phenylalanine, ortho-chlorophenylalanine, meta-chlorophenylalanine, and para-chlorophenylalanine were determined using the extended kinetic method with full entropy analysis to investigate the effect of chlorination on the PA of phenylalanine. The measured absolute PAs of the molecules are 907.9 ± 2.3, 901.9 ± 2.2, 889.0 ± 2.8, and 904.9 ± 3.1 kJ·mol −1 , respectively. The decrease and variations in the PAs upon chlorination are investigated based on the electronegativity of chlorine, polarizability, dipole moment, and the substituent effect. The effect of electronegativity of chlorine fails to explain differences in the PAs of the chlorine derivatives, and the ordering of the PAs is also not in line with polarizability.However, the ordering of dipole moments and substituent effects are, in part, consistent with that of the measured PAs except for the para and ortho derivatives, respectively. Thus, while no one molecular property fully explains the decrease in the absolute PA upon chlorination and its variation depending on the chlorination site, differences in dipole moments and the field effect provide the most plausible explanation for the observed changes.

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Gas-phase acid-base properties of homocysteine, homoserine, 5-mercaptonorvaline, and 5-hydroxynorvaline from the extended kinetic method

Cited by 9 publications

References 80 publications

Gas‐phase interactions of organotin compounds with cysteine

Gas‐phase interactions of organotin compounds with cysteine

Gas-phase acid-base properties of 1-aminocycloalkane-1-carboxylic acids from the extended kinetic method

Extended kinetic method study of the effect of ortho‐, meta‐, and para‐chlorination on the proton affinity of phenylalanine with full entropy analysis

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