Ionization constants and thermodynamic parameters of histidine and derivatives

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dc.contributor.authorBoschcov, Paulo [UNIFESP]
dc.contributor.authorSeidel, Wolfgang
dc.contributor.authorMuradian, José
dc.contributor.authorTominaga, Mineko
dc.contributor.authorPaiva, Antonio C.M. [UNIFESP]
dc.contributor.authorJuliano, Luiz [UNIFESP]
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2016-01-24T11:39:44Z
dc.date.available2016-01-24T11:39:44Z
dc.date.issued1983-01-01
dc.description.abstractThe pKa values for the proton dissociation of carboxyl, imidazolium, and ammonium groups for histidine and ten of its derivatives were determined electrometrically at seven temperatures in the range 10–40°C. The ΔH and ΔS values were estimated from the temperature dependence of the dissociation constants of histidine and its derivatives. These results and the pKa values compared in terms of inductive effect suggest an ion-dipole interaction between the protonated amino group and the unprotonated imidazole ring. The charge and the solvation effects of the neighboring groups are the main factors that determine the imidazole group pKa in histidine and its studied derivatives. The Nτ-H tautomer is favored over the Nπ-H by 1.6 kcal/mol, indicating that the inductive substituent effect at position 4 of the imidazole ring is the major component in determining this tautomeric preference.
dc.description.affiliationUNIV São Paulo,INST CHEM,SAN CARLOS,SP,BRAZIL
dc.description.affiliationUnifespEscola Paulista de Medicina. Department of Biophysics
dc.description.sourceWeb of Science
dc.format.extent34-44
dc.identifierhttp://dx.doi.org/10.1016/0045-2068(83)90005-6
dc.identifier.citationBioorganic Chemistry. San Diego: Academic Press Inc Jnl-comp Subscriptions, v. 12, n. 1, p. 34-44, 1983.
dc.identifier.doi10.1016/0045-2068(83)90005-6
dc.identifier.issn0045-2068
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/24918
dc.identifier.wosWOS:A1983SC97900004
dc.language.isoeng
dc.publisherAcademic Press Inc Jnl-comp Subscriptions
dc.relation.ispartofBioorganic Chemistry
dc.rightsAcesso restrito
dc.titleIonization constants and thermodynamic parameters of histidine and derivativesen
dc.typeArtigo
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