The enthalpies of interaction of some amides with urea in water at 25 °C
- 1 January 1988
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
- Vol. 84 (6), 1927-1940
- https://doi.org/10.1039/f19888401927
Abstract
The heterotactic interactions occurring in water at 25 °C between some simple amides [formamide (F), acetamide (A), N-methylformamide (NMF), N-methylacetamide (NMA), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N,N-diethylformamide (DEF) and N,N-diethylacetamide (DEA)] and the protein denaturant urea, have been investigated using enthalpy changes on mixing. The homotactic interactions of DEF and DMA have also been obtained from enthalpies of dilution and a redetermination of the enthalpy of dilution of A has also been performed. The results are discussed using the Savage and Wood additivity-of-groups approach and although this works quite well if all amidic groups are taken as being equivalent, much better agreement between calculated and experimental results is obtained if primary and secondary amide groups are assumed to be equivalent and in one category, and tertiary amidic groups are in another category. The enthalpies of interaction of urea with the groups in both categories are negative (i.e. are thermochemically favourable) but the tertiary amide group interacts with urea in water more favourably than primary and secondary amide groups. The somewhat surprising finding is commented on and addressed using some exact theories of solutions and is also considered with regard to urea-induced protein denaturation.This publication has 8 references indexed in Scilit:
- Excess enthalpies of ternary aqueous solutions of amides and ureas at 298.15 KJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1988
- Aqueous solutions containing amino acids and peptides. Part 24.—Free energetic and enthalpic coefficients for the interactions of some prolyl and sarcosyl terminally substituted compounds at 25 °CJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1986
- Aqueous solutions containing amino acids and peptides. Part 17.—Pairwise enthalpic coefficients for the interaction of N-acetyl-L-phenylalaninamide with some N-acetylamino acid amides at 25 °CJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1985
- Aqueous solutions containing amino acids and peptides. Part 16.—Solute–solute interactions in solutions containing some N-acetyl-N′-methylamino acid amidesJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1985
- Aqueous solutions containing amino acids and peptides. Part 12.—Enthalpy of interaction of α-alanine, α-aminobutyric acid, norvaline and norleucine with sodium chloride at 298.15 KJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1982
- Aqueous solutions containing amino acids and peptides. Part 13.—Enthalpy of dilution and osmotic coefficients of some N-acetyl amino acid amides and some N-acetyl peptide amides at 298.15 KJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1982
- Some novel inhibitors of porcine pancreatic elastaseBioorganic Chemistry, 1979
- Unfolding and refolding occur much faster for a proline-free proteins than for most proline-containing proteins.Proceedings of the National Academy of Sciences, 1977