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Titolo:
PURINE NUCLEOSIDE AND NUCLEOBASE CELL-MEMBRANE TRANSPORT IN GIARDIA-LAMBLIA
Autore:
BAUM KF; BERENS RL; MARR JJ;
Indirizzi:
UNIV COLORADO,HLTH SCI CTR,DEPT MED,4200 E 9TH AVE DENVER CO 80262 UNIV COLORADO,HLTH SCI CTR,DEPT BIOCHEM DENVER CO 80262
Titolo Testata:
The Journal of eukaryotic microbiology
fascicolo: 5, volume: 40, anno: 1993,
pagine: 643 - 649
SICI:
1066-5234(1993)40:5<643:PNANCT>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN-ERYTHROCYTES; ANIMAL-CELLS; INTESTINALIS TROPHOZOITES; SALVAGE; AFFINITY; METABOLISM; ANALOG;
Keywords:
ADENINE ARABINOSIDE; 7-DEAZAADENOSINE; DIPYRIDAMOLE; FORMYCIN-A; GIARDIA-LAMBLIA; MEMBRANE TRANSPORT; METABOLISM; NUCLEOBASE; NUCLEOSIDE; TRANSPORT KINETICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
K.F. Baum et al., "PURINE NUCLEOSIDE AND NUCLEOBASE CELL-MEMBRANE TRANSPORT IN GIARDIA-LAMBLIA", The Journal of eukaryotic microbiology, 40(5), 1993, pp. 643-649

Abstract

Giardia lamblia is dependent on the salvage of preformed purines and pyrimidines. This study investigated purine nucleoside and nucleobase transport utilizing rapid uptake determinations. Nucleoside substrate/velocity curves exhibited the hyperbolic kinetics of a saturable carrier-mediated system. Deoxynucleosides exhibited a much lower affinity for the transporter. Inhibition studies confirmed the relative carrier affinities of these ribonucleosides and deoxyribonucleosides. The nucleobase adenine did not exhibit saturation kinetics at a comparable substrate range, and did not inhibit nucleoside transport. Dipyridamole markedly inhibited nucleoside but not nucleobase transport, confirming the separate entry pathways. When cells were depleted of ATP, the velocity of nucleoside and nucleobase transport was unchanged, indicating that it is a non-energy-dependent process. Three nucleoside analogs, formycin A, adenine arabinoside and 7-deazaadenosine, were studied. Transport kinetics ranged widely among this group and could not completely account for their cytotoxic effect. When the apparent Km and Vmax ofthe nucleosides were compared, an approximately linear relationship (r2 = 0.95) was noted. This suggests that a high affinity of the nucleoside permease for the substrate retards disassociation of the substrate-carrier complex, slowing net influx.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/21 alle ore 15:27:44