Reconstitution of the lactate carrier from rat skeletal-muscle sarcolemma.
The lactate carrier was solubilized from purified rat skeletal-muscle sarcolemma with the detergent decanoyl-N-methyl-glucamide and the solubilized carrier was reconstituted into phospholipid vesicles. Reconstituted proteoliposomes showed a faster time course of L-lactate uptake than did protein-free liposomes. The rate of L-lactate uptake into the proteoliposomes was inhibited by the lactate-transport inhibitors p-chloromercuribenzenesulphonate, diethyl pyrocarbonate, alpha-cyano-4-hydroxycinnamate and quercetin. In contrast, the anion-exchange inhibitor DIDS (4,4'-di-isothiocyanostilbene-2,2'-disulphonate) had almost no effect on the uptake. The extent of L-lactate uptake at equilibrium was not affected by the presence of the transport inhibitors, but was sensitive to osmotic strength. L-Lactate and pyruvate, but not D-lactate, inhibited L-lactate uptake when present at 10-fold excess. The properties of L-lactate transport in reconstituted proteoliposomes were similar to those observed in native sarcolemmal vesicles, i.e. the lactate carrier seems to retain its transport characteristics during the solubilization and reconstitution steps.
Wibrand
F
F
August Krogh Institute, University of Copenhagen, Denmark.
Juel
C
C
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D007773:Lactates / Q000378:metabolism*; D008081:Liposomes; D008297:Male; D027501:Monocarboxylic Acid Transporters; D009132:Muscles / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000378:metabolism*
D002352:Carrier Proteins; D007773:Lactates; D008081:Liposomes; D027501:Monocarboxylic Acid Transporters; D011510:Proteolipids; C020485:proteoliposomes; D002731:4-Chloromercuribenzenesulfonate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid