Ionization constants and thermal stabilities of uracil and adenine under hydrothermal conditions as measured by in situ UV–visible spectroscopy

Balodis, Erik C; Madekufamba, Melerin; Trevani, Liliana; Tremaine, Peter R.

doi:10.1016/j.gca.2012.06.023

Cited by 10 publications

(3 citation statements)

References 71 publications

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“…Ura is a pyrimidine base capable of tautomerization as lactam and lactim forms [17]. It was found that the lactam tautomer predominates in a neutral medium, transforming into a monoanion as pH rises (pH ≥ 9.52) [18,19]. The RRSU program [20], which is based on a modified Brinkley approach, was used to determine the fractional distribution of different Ura forms, depending on the pH of the medium.…”

Section: Resultsmentioning

confidence: 99%

Molecular Interactions between L-Phenylalanine and Uracyl in an Aqueous Buffer Solution at 293–323 K

Tyunina

2019

Russ. J. Phys. Chem.

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Interactions between L-phenylalanine (Phe) and uracyl (Ura) in an aqueous buffer solution (pH 7.35) are analyzed via densimetry and differential scanning calorimetry. Experimental values of the density and specific heat capacity of Ura-buffer, Phe-buffer, and Phe-Ura-buffer systems are obtained at T = (293. 15, 303.15, 313.15, and 323.15) K, Ura concentrations of 0.0040 to 0.0365 mol kg −1 , and a constant Phe concentration of 0.0120 mol kg −1 . It is shown that the interaction between Phe and Ura is accompanied by the formation of a complex with the composition 1 : 2. It is established that the partial molar properties of Ura when it is transferred from the buffer to the buffer Phe solution are positive for the volume and negative for the heat capacity in the investigated range of temperatures. The final results are discussed using the Gurney model.

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Section: Resultsmentioning

confidence: 99%

Molecular Interactions between L-Phenylalanine and Uracyl in an Aqueous Buffer Solution at 293–323 K

Tyunina

2019

Russ. J. Phys. Chem.

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“…As we mentioned before, a significant number of prebiotic experiments, simulating submarine hydrothermal vent conditions, only focus on the stability and decomposition of organic molecules at high temperatures and high pressures (i.e. >100°C and >10 bar) (Larralde et al, 1995;Levy and Miller, 1998;Alargov et al, 2002;Sato et al, 2004;Abdelmoez et al, 2007;Seward, 2007a, 2007b;Klingler et al, 2007;Balodis et al, 2012). Despite the tremendous complexity of submarine hydrothermal environments, only recently a few experiments have studied the role of different variables, such as minerals (Andersson and Holm, 2000;McCollom and Seewald, 2003;Ito et al, 2006Ito et al, , 2009McCollom, 2013;Burcar et al, 2015;Dalai et al, 2016), dissolved ions and gases (Marshall, 1994;Yamaoka et al, 2007;Franiatte et al, 2008;Chandru et al, 2013;Estrada et al, 2017), the quenching effect (350 -2°C) (Ogasawara et al, 2000;Ogata et al, 2000;Islam et al, 2003;Kawamura and Shimahashi, 2008), the pH effect and the redox state (Yamaoka et al, 2007;Sakata et al, 2010;Lee et al, 2014) on the stability and transformation of different organic compounds (for a detailed review, see Colín-García et al, 2016 and have improved the understanding of the role of physicochemical variables (coupled or individually) on the fate of organic molecules in these environments.…”

Section: Submarine Hydrothermal Vent Systems: Dynamic Systemsmentioning

confidence: 99%

Submarine hydrothermal vent systems: the relevance of dynamic systems in chemical evolution and prebiotic chemistry experiments

Villafañe-Barajas

Colín-García

2021

International Journal of Astrobiology

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Since their discovery, submarine hydrothermal vent systems have been pointed out as important places where chemical evolution on Earth could have occurred; and their role in the process has been highlighted. Similarly, some hypotheses have considered these systems in origin of life scenarios. In this way, many experiments have been developed, and the knowledge about these systems has increased. Due to their complexity, many experimental simulations have only included a few of the geochemical variables present in these environments, pressure and temperature. Other main variables have hardly been included, such as mineralogy, thermal and pH gradients, dissolved ions and/or redox reactions. As it has been understood, the dynamism and heterogeneity of these environments are huge, and it comprises different scales, from single vents to full hydrothermal fields. However, the vast majority of experiments focus on a specific part of these systems and do not include salinity, mineralogy and pH gradients. For this reason, in this paper, we pointed out some considerations about how this dynamism can be interpreted, and included in some models, as well their importance in prebiotic chemistry experiments and their extrapolations regarding the hypothesis about the origins of life.

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“…To achieve this, the following was necessary: The objects of this study were uracil and cytosine as nucleic bases of the pyrimidine series, the structures of which are shown in Figure 1. In a neutral solution at pH < 9.5, uracil and cytosine take a lactam molecular form [8]. Peptides with different compositions and structures were chosen for the study.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical Study of the Interaction of Cytosine and Uracil with Peptides in a Buffered Saline: Complex Formation with beta-Endorphin 30-31 (Human), L-Glutathion (Reduced) and α-L-Alanyl-L-Tyrosine

Barannikov

Smirnov

Mezhevoi

et al. 2023

IJMS

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The complex formation of uracil and cytosine with glycyl-L-glutamic acid (β-endorphin 30-31), γ-L-glutamyl-L-cysteinyl-glycine (glutathione reduced), α-L-alanyl-L-tyrosine, and α-L-alanyl-α-L-alanine in a buffered saline has been studied using dissolution calorimetry. The values of the reaction constant, the change in Gibbs energy, enthalpy, and entropy were obtained. It is shown that the ratio of the enthalpy and entropy factors depends on the charge of the peptide ion, and the number of H-bond acceptors in the peptide structure. The contributions of interaction between charged groups and polar fragments, hydrogen bonding, and stacking interaction are discussed, taking into account the effect of solvent reorganization around the reactant molecules.

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Ionization constants and thermal stabilities of uracil and adenine under hydrothermal conditions as measured by in situ UV–visible spectroscopy

Cited by 10 publications

References 71 publications

Molecular Interactions between L-Phenylalanine and Uracyl in an Aqueous Buffer Solution at 293–323 K

Molecular Interactions between L-Phenylalanine and Uracyl in an Aqueous Buffer Solution at 293–323 K

Submarine hydrothermal vent systems: the relevance of dynamic systems in chemical evolution and prebiotic chemistry experiments

Thermochemical Study of the Interaction of Cytosine and Uracil with Peptides in a Buffered Saline: Complex Formation with beta-Endorphin 30-31 (Human), L-Glutathion (Reduced) and α-L-Alanyl-L-Tyrosine

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