CAPILLARY ZONE ELECTROPHORESIS OF PEPTIDES - PREDICTION OF THE ELECTROPHORETIC MOBILITY AND RESOLUTION

Giuseppina Nocca, Massimo Castagnola, Loredana Cassiano, Diana Valeria Rossetti, Bruno Giardina, I Messana, R Rabino

Risultato della ricerca: Contributo in rivistaArticolo in rivista

42 Citazioni (Scopus)

Abstract

The determination of the pK(a) values of some selected peptides of similar size was performed by microtitration, which makes possible an accurate determination of the peptide charge as a function of the solution pH. Capillary zone electrophoresis separation of these peptides on modified capillaries at acidic pH showed that the electrophoretic mobility correlates with the peptide charge. This observation suggests that when an appropriate charge value is used, the basic electrophoretic equation is respected and, at least at a peptide charge value less than I, the utilization of alternative semi-empirical predictions is not necessary. As a general rule, a peptide separation at acidic pH values is to be preferred to that at basic pH values. In fact, at basic pH a separation in the absence of both electroosmotic flow and of spurious interactions between the peptides and the inner wall of the capillary is difficult, owing to the instability of capillary modification. Further, from the differences in the peptide charge, a prediction of the best resolution as a function of the pH could be obtained; in fact, the resolution, for peptides of similar size and in the absence of electroosmotic flow, is connected to a simple equation, where the principal term depends on the effective charge of the peptides, which is a function of the pH of the solution and the pK, values of the peptides. The predictions of resolution at acidic pH agreed well with the experimental results; the spatial resolution measured in the separation of met- and leu-enkephalin was virtually coincident with the predicted resolution; in the case of a mixture of four model tetrapeptides of sequence GGNA, GGQA, GGDA and GGEA some anomalous results with respect to the predicted resolutions were observed. Nevertheless, an acceptable prediction can also be made in this case.
Lingua originaleEnglish
pagine (da-a)87-97
Numero di pagine11
RivistaJOURNAL OF CHROMATOGRAPHY B. BIOMEDICAL APPLICATIONS
Volume656
DOI
Stato di pubblicazionePubblicato - 1994

Keywords

  • CAPILLARY

Fingerprint Entra nei temi di ricerca di 'CAPILLARY ZONE ELECTROPHORESIS OF PEPTIDES - PREDICTION OF THE ELECTROPHORETIC MOBILITY AND RESOLUTION'. Insieme formano una fingerprint unica.

Cita questo