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Titolo:
REEXAMINATION OF HEXOSE EXCHANGES USING RAT ERYTHROCYTES - EVIDENCE INCONSISTENT WITH A ONE-SITE SEQUENTIAL EXCHANGE MODEL, BUT CONSISTENT WITH A 2-SITE SIMULTANEOUS EXCHANGE MODEL
Autore:
NAFTALIN RJ; RIST RJ;
Indirizzi:
UNIV LONDON KINGS COLL,DIV BIOMED SCI,PHYSIOL GRP LONDON WC2R 2LS ENGLAND
Titolo Testata:
Biochimica et biophysica acta. Biomembranes
fascicolo: 1, volume: 1191, anno: 1994,
pagine: 65 - 78
SICI:
0005-2736(1994)1191:1<65:ROHEUR>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
GLUCOSE TRANSPORTER; SUGAR-TRANSPORT; CARRIER MODEL; CYTOCHALASIN-B; CELLS; KINETICS; BINDING; MEMBRANE; REJECTION;
Keywords:
EXCHANGE TRANSPORT KINETICS; RED CELL; MANNOSE; 3-O-METHYL-D-GLUCOSE; 2-DEOXY-D-GLUCOSE; (RAT);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
R.J. Naftalin e R.J. Rist, "REEXAMINATION OF HEXOSE EXCHANGES USING RAT ERYTHROCYTES - EVIDENCE INCONSISTENT WITH A ONE-SITE SEQUENTIAL EXCHANGE MODEL, BUT CONSISTENT WITH A 2-SITE SIMULTANEOUS EXCHANGE MODEL", Biochimica et biophysica acta. Biomembranes, 1191(1), 1994, pp. 65-78

Abstract

(1). The kinetic parameters of zero-trans net uptake and infinite-trans uptake of 3-O-methyl-D-glucoside, 2-deoxy-D-glucose and D-mannose into rat red cells at 24 degrees C were measured after taking account of the linear diffusion components of flux. (2). Zero-trans exits of 3-O-methyl-D-glucoside and D-mannose from rat cells were also measured. (3). After correction for linear flux via non-specific routes, the V-max of zero-trans uptake of 3-O-methyl-D-glucoside was significantly higher, (1.25 +/- 0.06 mu mol(10 min)(-1)(ml cell water)(-1)) than the corresponding parameters of mannose or 2-deoxy-D-glucose, (0.33 +/- 0.01 and 0.39 +/- 0.01 mu mol(10-min)(-1)(ml cell water)(-1), respectively; P < 0.001). (4). After correction for linear flux via non-specific uptake routes, the V-max of zero-trans exit of 3-O-methyl-D-glucoside is significantly higher (1.70 +/- 0.1 mu mol(10 min)(-1)(ml cell water)(-1)) than the corresponding value for mannose exit flux, (1.10 +/- 0.1 mu mol(10 min)(-1)(ml cell water)(-1); P < 0.001). (5). The acceleration ratio, i.e., the ratio of infinite-trans influx V-max/zero-transinflux V-max of mannose by mannose (9.12 +/- 0.03) is significantly higher than that of 3-O-methyl-D-glucose by 3-O-methyl-D-glucose (2.77 /- 0.14)(P < 0.001). (6). The one-site simple carrier model of glucose transport in which sugar exchange is viewed as a sequential process,predicts that the acceleration ratio of the more rapidly moving sugar3-O-methyl-D-glucose by 3-O-methyl-D-glucose should be greater than that of the slower sugar, mannose by mannose. Hence, the observed findings are inconsistent with the one-site model, but confirm the earlier disputed studies of Miller, D.M. (1968; Biophys. J. 8, 1329-1338). (7). A two-site model, in which sugar exchange is considered as a simultaneous process, predicts that the acceleration ratio of mannose influx by mannose should be higher than for 3-O-methyl-D-glucose by 3-O-methyl-D-glucose. The data are, therefore, consistent with a two-site model.
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Documento generato il 20/01/21 alle ore 15:52:41