Helvetica Chimica Acta · 1991 · 13 citations · 30 references
Natural SciencesBiochemistryChemistryPolymer ChemistryProtein BiochemistryTheoretical ChemistryAcid-base ChemistryAmino Acid ChemistryPeptide Bond ChemistryPeptide ChemistryPka DeterminationProtein ChemistryIonic StrengthIonic Strength EffectsPh DependencePh Dependence Of StabilityPh StabilityPh-dependent Binding KineticsPh-dependent Biomolecular InteractionsPyridoxal Phosphate Chemistry
Abstract We determined the apparent equilibrium constant of formation, K pH , of the Schiff bases of pyridoxal 5′‐phosphate (PLP) and poly‐ and copolymers containing L ‐lysine, as a function of pH at 25° and a constant ionic strength of 0.1 M . The K pH values obtained at acidic and neutral pH were larger that those reported for Schiff bases of PLP and hexylamine. We determined calorimetrically Δ H of formation of Schiff bases of PLP and poly( L ‐lysine) (−4.5′kcal/mol), and PLP and hexylamine (−3.4 kcal/mol) at pH 7.00. Semi‐empirical theoretical calculations (INDO and AMI methods) of a model compound of Schiff base of PLP and polypeptide containing L ‐lysine show the capability of specific interactions between groups of PLP and the peptide skeleton.
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