title: Adsorption of an ionic homopolypeptide to a flat surface induced by pH change.
abstract: This paper presents a model for pH-dependent adsorption of an ionic homopolypeptide with secondary structure on a flat surface. This model is developed by generalization of a discrete model of semistiff chain with short-range interaction, between homopolypeptide chain and surface. The presence of intramolecular repulsive interaction as well as secondary structure is introduced here by modified Zimm-Bragg stabilization parameters. The model predicts that in the case of low degree of ionization, the adsorption behaviour of an ionic and non-ionic homopolypeptide are qualitatively similar (i.e. both show a second-order phase-transition, characteristic of this phenomenon). We also illustrate the prediction of the model about the critical absorption energy in the case of selective interaction, and show that a discontinuity in the melting-temperature behaviour appears when the pH is tuned to a critical pH value (pHc).
authors.affiliation: Instituto de Matematica Aplicada San Luis (Conicet), Universidad Nacional de San Luis, Argentina.
authors.forename: J
authors.initials: J
authors.lastname: Vila
authors.forename: J L
authors.initials: JL
authors.lastname: Alessandrini
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D010455:Peptides / Q000502:physiology*
chemical_list: D010455:Peptides