463-79-6Relevant articles and documents
Carbonic anhydrase activity of dinuclear CuII complexes with patellamide model ligands
Comba, Peter,Gahan, Lawrence R.,Hanson, Graeme R.,Maeder, Marcel,Westphal, Michael
, p. 3144 - 3152 (2014)
The dicopper(ii) complexes of six pseudo-octapeptides, synthetic analogues of ascidiacyclamide and the patellamides, found in ascidians of the Pacific and Indian Oceans, are shown to be efficient carbonic anhydrase model complexes with kcat up to 7.3 × 103 s-1 (uncatalyzed: 3.7 × 10-2 s-1; enzyme-catalyzed: 2 × 10 5-1.4 × 106 s-1) and a turnover number (TON) of at least 1700, limited only by the experimental conditions used. So far, no copper-based natural carbonic anhydrases are known, no faster model systems have been described and the biological role of the patellamide macrocycles is so far unknown. The observed CO2 hydration rates depend on the configuration of the isopropyl side chains of the pseudo-octapeptide scaffold, and the naturally observed R*,S*, R*,S* geometry is shown to lead to more efficient catalysts than the S*,S*,S*,S* isomers. The catalytic efficiency also depends on the heterocyclic donor groups of the pseudo-octapeptides. Interestingly, the dicopper(ii) complex of the ligand with four imidazole groups is a more efficient catalyst than that of the close analogue of ascidiacyclamide with two thiazole and two oxazoline rings. The experimental observations indicate that the nucleophilic attack of a CuII- coordinated hydroxide at the CO2 carbon center is rate determining, i.e. formation of the catalyst-CO2 adduct and release of carbonate/bicarbonate are relatively fast processes.
Gerster, R.
, p. 339 - 348 (1971)
Enzyme-embedded metal-organic framework membranes on polymeric substrates for efficient CO2 capture
Zhang, Yiming,Wang, Huixian,Liu, Jindun,Hou, Jingwei,Zhang, Yatao
, p. 19954 - 19962 (2017)
In this work, carbonic anhydrase (CA) molecules were embedded into metal-organic frameworks (MOFs) via physical absorption and chemical bonds, which could overcome the enzymatic inactivation and the poor separation property of pristine MOF materials. And then, these nanocomposites (enzyme-embedded MOFs) as the crystal seeds were in situ grown on oriented halloysite nanotube layers to develop novel biocatalytic composite membranes. These membranes exhibited optimal separation performance with a CO2/N2 selectivity of 165.5, about 20.9 fold higher than that of the membrane without embedded CA molecules, surpassing the Robeson upper bound (2008). At the same time, the CO2 permeance increased about 3.2 fold (from 7.6 GPU to 24.16 GPU). Importantly, the biocatalytic composite membranes showed good stability and mechanical properties and were easily scalable, which could be extended to industrial applications.
Inhibition properties of new amino acids for prevention of hydrate formation in carbon dioxide-water system: Experimental and modeling investigations
Roosta, Hadi,Dashti, Ali,Mazloumi, S. Hossein,Varaminian, Farshad
, p. 656 - 663 (2016)
In the present work, the effect of new structures of amino acids is studied for prevention of hydrate formation in the carbon dioxide-water system. These amino acids consist of L-proline (as amino acid with nonpolar side chain), L-serine and L-glutamine (
Powell, E. O.
, p. 401 (1940)
Sharma, M. M.,Dankwarts, P. V.
, p. 386 - 395 (1963)
Gatlow,Gerwarth
, p. 78,81, 84-88 (1968)
Influence of Ammonium Acetate Concentration on Receptor-Ligand Binding Affinities Measured by Native Nano ESI-MS: A Systematic Study
Gavriilidou, Agni F. M.,Gülbakan, Basri,Zenobi, Renato
, p. 10378 - 10384 (2015)
Native electrospray ionization (ESI) mass spectrometry (MS) is a powerful technique for analyzing biomolecules in their native state. However, ESI-MS is incompatible with nonvolatile solution additives. Therefore, biomolecules have to be electrosprayed from a solution that differs from their purification or storage buffer, often aqueous ammonium acetate (AmAc). In this study, the effect of the ionic strength on the dissociation constants of six different noncovalent complexes, that cover interactions present in many biological systems, was investigated. Complexes were electrosprayed from 10 mM, 50 mM, 100 mM, 300 mM, and 500 mM aqueous AmAc. For all systems, it was shown that the binding affinity is significantly influenced by the ionic strength of the solution. The determined dissociation constant (Kd) was affected more than 50% when increasing the AmAc concentration. The results are interpreted in terms of altered ionic interactions induced by the solution. This work emphasizes the modulating effect of the ions on noncovalent interactions and the importance of carefully choosing the AmAc concentration for quantifying the receptor-ligand binding strengths.
Welch, M. J.,Lifton, J. F.,Seck, J. A.
, p. 3351 - 3356 (1965)
Lynn
, p. 687 (1965)
Comparative Analysis of Acyclovir Esters Stability in Solutions: The Influence of the Substituent Structure, Kinetics, and Steric Effects
Lesniewska, Monika A.,Gola, Micha?,Dutkiewicz, Zbigniew,Muszalska, Izabela
, p. 724 - 733 (2015)
Reversed-phase high-performance liquid chromatography has been applied to the determination of acyclovir (ACV) esters such as acetate, isobutyrate, pivalate, ethoxycarbonate, and nicotinate. All analyses were carried out at laboratory temperature using a column LiChrospher RP-18 (250 × 4 mm, 5 μm) and a proper mobile phase consisting of acetonitrile and phosphate buffer (pH 6 or 6.7) or acetonitrile and potassium dihydrogen phosphate, and acetic acid. The methods were validated by the determination of the following parameters: selectivity, precision, accuracy, and linearity. Kinetic studies on the hydrolysis were investigated in solutions at 310 K over the pH range 0.42-1.38. The pH-profiles indicated specific acid-catalyzed and spontaneous water-catalyzed degradation. The stability of the studied ACV esters were determined not only by steric factors. In the case of ethoxycarbonyl ester of ACV, the hydrolysis was a two-step reaction.
Spectroscopic observation of matrix-isolated carbonic acid trapped from the gas phase
Bernard, Juergen,Seidl, Markus,Kohl, Ingrid,Liedl, Klaus R.,Mayer, Erwin,Galvez, Oscar,Grothe, Hinrich,Loerting, Thomas
, p. 1939 - 1943 (2011)
Against all odds: Carbonic acid molecules were trapped from the gas phase in a solid noble-gas matrix at 2H and and 13C isotopologues were also examined. Gas-phase carbonic acid is thought to exist as a 1:10:1 mixture of two monomeric conformers and the cyclic dimer (H2CO3)2. This data is vital in the search for gas-phase carbonic acid in astrophysical environments.
Tunnelling in carbonic acid
Wagner, J. Philipp,Reisenauer, Hans Peter,Hirvonen, Viivi,Wu, Chia-Hua,Tyberg, Joseph L.,Allen, Wesley D.,Schreiner, Peter R.
supporting information, p. 7858 - 7861 (2016/07/06)
The cis,trans-conformer of carbonic acid (H2CO3), generated by near-infrared radiation, undergoes an unreported quantum mechanical tunnelling rotamerization with half-lives in cryogenic matrices of 4-20 h, depending on temperature and host material. First-principles quantum chemistry at high levels of theory gives a tunnelling half-life of about 1 h, quite near those measured for the fastest rotamerizations.
