title: Determination of dissociation constant of phosphinate group in phosphinic pseudopeptides by capillary zone electrophoresis.
abstract: Capillary zone electrophoresis (CZE) was used for determination of dissociation constant of phosphinate group in phosphinic pseudopeptides, i.e. peptides where one peptide bond is substituted by phosphinic acid moiety -PO2--CH2-. The dissociation constants were determined for a set of newly synthesized pseudopeptides derived from a structure N-Ac-Val-Ala(psi)(PO2--CH2)Leu-His-NH2 by nonlinear regression of experimentally measured pH dependence of their effective electrophoretic mobilities. CZE experiments were carried out in Tris-phosphate background electrolytes in the pH range 1.4-3.2. The pseudopeptides were synthesized as a mixture of four diastereomers, the separation of which was achieved in most cases. Moreover, differences of the effective mobilities of the pseudopeptide diastereomers enabled simultaneous determination of the dissociation constant of their phosphinate group without necessity of previous isolation of individual isomers.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague.
authors.forename: Dugan
authors.initials: D
authors.lastname: Koval
authors.forename: Václav
authors.initials: V
authors.lastname: Kasicka
authors.forename: Jifí
authors.initials: J
authors.lastname: Jirácek
authors.forename: Michaela
authors.initials: M
authors.lastname: Collinsová
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Garrow
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010455:Peptides / Q000737:chemistry*; D010721:Phosphinic Acids / Q000737:chemistry*
chemical_list: D010455:Peptides; D010721:Phosphinic Acids