Exploring the evaluation of net charge, hydrodynamic size and shape of peptides through experimental electrophoretic mobilities obtained from CZE.
This work explores the validity of simple CZE models to analyze the electrophoretic mobilities of 102 peptides reported in literature. These models are based mainly on fundamental physicochemical theories providing analytical expressions amenable to relatively simple numerical analysis. Thus, the Linderstrøm-Lang capillary electrophoresis model (LLCEM) and its perturbed version (PLLCEM), proposed and applied previously to the CZE of globular proteins, are adapted and used here for peptides. Also the effects of pK-shifts on net charge, hydration and hydrodynamic size and shape of peptides are analyzed and discussed. Emphasis is placed on the fact that these parameters are physically coupled, and thus a variation in the net charge may produce an appreciable change in the hydrodynamic size of peptides. Within the framework of CZE, peptides may be assumed as having a hydrodynamic volume associated with either spherical or spheroidal particles. The effects on peptide net charge and hydrodynamic size, of electrostatic interaction between a pair of charged groups in the chain and electrical permitivitty around the peptide domain are studied. The predictions of the PLLCEM and LLCEM are in good agreement with results reported previously in the literature. Several limitations concerning these models and some needs for further research are also described.
Piaggio
Maria V
MV
Cátedra de Bioquímica Básica de Macromoléculas, Facultad de Bioquímicay Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
Peirotti
Marta B
MB
Deiber
Julio A
JA
D000595:Amino Acid Sequence; D019075:Electrophoresis, Capillary; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D014867:Water / Q000737:chemistry
D010455:Peptides; D014867:Water