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Titolo:
NATURE OF THE ELEMENTS TRANSPORTING LONG-CHAIN FATTY-ACIDS THROUGH THE RED-CELL MEMBRANE
Autore:
BOJESEN IN; BOJESEN E;
Indirizzi:
UNIV COPENHAGEN,PANUM INST,DEPT MED BIOCHEM & GENET,LAB MED BIOCHEM B,BLEGDAMSVEJ 3 DK-2200 COPENHAGEN N DENMARK
Titolo Testata:
The Journal of membrane biology
fascicolo: 3, volume: 163, anno: 1998,
pagine: 169 - 181
SICI:
0022-2631(1998)163:3<169:NOTETL>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
BOVINE SERUM-ALBUMIN; PLASMA-MEMBRANE; ERYTHROCYTE GHOST; PALMITATE BINDING; PROTEIN; INHIBITION; ARACHIDONATE; KINETICS; SYSTEMS; OLEATE;
Keywords:
DOCOSAHEXAENOIC ACID (DELTA 4,7,10,13,16,19); LINOLEIC ACID; RED CELL MEMBRANE; TRANSPORTING ELEMENTS; TRANSPORT KINETICS; FATTY ACID TRANSPORT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
39
Recensione:
Indirizzi per estratti:
Citazione:
I.N. Bojesen e E. Bojesen, "NATURE OF THE ELEMENTS TRANSPORTING LONG-CHAIN FATTY-ACIDS THROUGH THE RED-CELL MEMBRANE", The Journal of membrane biology, 163(3), 1998, pp. 169-181

Abstract

Docosahexaenoic acid is found to be bound to three equivalent sites on albumin with the same affinities as palmitic acid at 0-38 degrees C,which demonstrates that ethene-1,2-diyl- and methylene-groups contribute equally to the affinity. The equilibrium dissociation constants (K(dm)s) for red cell membrane binding sites of linoleic- and docosahexaenoic acid at pH 7.3 are determined at temperatures between 0 and 37 degrees C. The temperature-independent capacities for binding are 12 +/- 1 and 25.4 +/- 3.0 nmoles g(-1) ghosts respectively. Double isotope binding experiments reveal that the unsaturated fatty acids: arachidonic-, linoleic-, docosahexaenoic-, and oleic acid have partially sharedcapacities in ratios approximately 1:2:4:5, in contrast to the noncompetitive binding of palmitic acid. The observations suggest a two-tierbinding limitation. One is the number of protein sites binding fatty acid anions electrostatically and the other is the number of suitable annular lipids adaptively selected among membrane lipids by the hydrocarbon chain. These competition conditions are confirmed by measurements of the tracer exchange efflux at near 0 degrees C from albumin-free and albumin-filled ghosts of linoleic- and docosahexaenoic acid, either alone or in the presence of arachidonic- and palmitic acid. Under equilibrium conditions, the calculated ratios of inside to outside membrane binding is below 0.5 for four unsaturated fatty acids. The unidirectional rate constants of translocation between the inside and the outside correlate with the number of double bonds in these fatty acids, which are also correlated with the dissociation rate constants of the complexes with albumin. The membrane permeation occurs presumably by binding of the anionic unsaturated fatty acids to an integral protein followed by channeling of the neutral form between opposite binding sites of the protein through annular lipids encircling the protein.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/21 alle ore 14:07:23