L(+)-lactate binding to a protein in rat skeletal muscle plasma membranes.
Biochemical studies were conducted to determine the location of a putative lactate transport protein in rat skeletal muscle plasma membranes (PM). PM (50-100 micrograms protein) were incubated with [U-14C] L(+)-lactate, in the presence or absence of unlabeled monocarboxylates or potential inhibitors, after which proteins were separated by SDS-PAGE. Gel slices (2 mm) were cut and analyzed for 14C. [U-14C] L(+)-lactate was bound to plasma membranes in the 30 to 40 kDa molecular mass range. Binding of [U-14C] L(+)-lactate was inhibited by N-ethylmaleimide, unlabeled L-lactate and pyruvate, and in a dose dependent manner by alpha-cyano-4-hydroxycinnamate (r = 0.995), but not by cytochalasin-B. The inhibition of [U-14C] L(+)-lactate binding was similar to the inhibition of lactate transport. Therefore the transport of L(+)-lactate across skeletal muscle plasma membranes involves a polypeptide of 30 to 40 kDa.
McCullagh
K J
KJ
Department of Kinesiology, University of Waterloo, Ontario.
Bonen
A
A
D000818:Animals; D002250:Carbon Radioisotopes; D002264:Carboxylic Acids / Q000494:pharmacology; D002352:Carrier Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003373:Coumaric Acids / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005033:Ethylmaleimide / Q000494:pharmacology; D007773:Lactates / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008970:Molecular Weight; D027501:Monocarboxylic Acid Transporters; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding / Q000187:drug effects; D011773:Pyruvates / Q000494:pharmacology; D051381:Rats; D012508:Sarcolemma / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate
D002250:Carbon Radioisotopes; D002264:Carboxylic Acids; D002352:Carrier Proteins; D003373:Coumaric Acids; D007773:Lactates; D008565:Membrane Proteins; D027501:Monocarboxylic Acid Transporters; D011773:Pyruvates; C007175:alpha-cyano-4-hydroxycinnamate; D012967:Sodium Dodecyl Sulfate; D003571:Cytochalasin B; D005033:Ethylmaleimide