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Titolo:
Specific adsorption of phosphate ions on proteins evidenced by capillary electrophoresis and reversed-phase high-performance liquid chromatography
Autore:
Rabiller-Baudry, M; Chaufer, B;
Indirizzi:
Univ Rennes 1, INRA, Lab Proc Separat, UC 991, F-35042 Rennes, France UnivRennes 1 Rennes France F-35042 arat, UC 991, F-35042 Rennes, France
Titolo Testata:
JOURNAL OF CHROMATOGRAPHY B
fascicolo: 1, volume: 753, anno: 2001,
pagine: 67 - 77
SICI:
1387-2273(20010325)753:1<67:SAOPIO>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHYSICOCHEMICAL ENVIRONMENT; ULTRAFILTRATION; MOBILITIES; PEPTIDES; LYSOZYME;
Keywords:
phosphate ions; proteins;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
17
Recensione:
Indirizzi per estratti:
Indirizzo: Rabiller-Baudry, M Univ Rennes 1, INRA, Lab Proc Separat, UC 991, Campus Beaulieu,Batiment 10A,263 Ave Gen Leclerc, F-35042 Rennes, France Univ Rennes 1 Campus Beaulieu,Batiment 10A,263 Ave Gen Leclerc Rennes France F-35042
Citazione:
M. Rabiller-Baudry e B. Chaufer, "Specific adsorption of phosphate ions on proteins evidenced by capillary electrophoresis and reversed-phase high-performance liquid chromatography", J CHROMAT B, 753(1), 2001, pp. 67-77

Abstract

Specific adsorption of phosphate ions at pH=7.0 was studied on different proteins, either counter-ions of phosphate (lysozyme, lactoferrin) or co-ionof phosphate (alpha -lactalbumin). The theoretical electrophoretic mobility of globular proteins lysozyme and alpha -lactalbumin (apo and hole (+1 calcium per molecule) forms) was compared with those measured by capillary electrophoresis in phosphate at pH 7.0, versus the ionic strength (I) in the range 0-0.775 mol L-1. The specific adsorption of phosphate ions was evidenced by difference. From the experimental charge number (Z(eff)) of protein in phosphate medium, a phosphate content per protein molecule was determined at pH=7.0. For lactoferrin (pI=8-9), the electrophoretic mobility (mu) was constant and negative, highlighting a charge reversal due to phosphate adsorption. For alpha -lactalbumin (holo form) experimental mu was roughly constant and more negative than predicted. Z(eff) increased continuously from -4 to -11 in the ionic strength range from 0.005 to 0.775 mol l(-1), respectively. Accordingly, one to six phosphates were bound per molecule, respectively. For lysozyme, experimental electrophoretic mobility was positive but lowerthan predicted. Z(eff) was only discrete values +5 for I in the range 0.001-0.020 mol l(-1) and about +3 in the range 0.050-0.500 mol l(-1), whereas the theoretical Z value was +7 at pH=7.0. Lysozyme bounds one phosphate at low ionic strength and about two - three at higher ionic strength. Reversed-phase HPLC confirms that adsorption of phosphate is different forthe three proteins. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 12:51:10