N-terminal protein sequence analysis of the rabbit erythrocyte lactate transporter suggests identity with the cloned monocarboxylate transport protein MCT1.
An improved purification for the rabbit erythrocyte lactate transporter, using aminoethyl-Sepharose chromatography, is described. The process of purification of the 40-50 kDa transporter, labelled with 4,4'-diisothiocyanostilbene-2,2'-disulphonate (DIDS), was followed by Western blotting with anti-DIDS antibodies [Poole, R. C. and Halestrap, A. P. (1992) Biochem. J. 283, 855-862]. Fractions highly-enriched in transporter were further purified by SDS/PAGE and the 40-50 kDa DIDS-labelled polypeptide was subjected to N-terminal protein sequencing. This analysis identified the first 16 amino acids of the protein. With the exception of one conservative substitution, this protein sequence is identical to the N-terminal protein sequence predicted from a cDNA isolated from Chinese hamster ovary cells that encode a monocarboxylate transporter, MCT1 [Kim Garcia, C., Goldstein, J. L., Pathak, R. K., Anderson, R. G. W. and Brown, M. S. (1994) Cell 76, 865-873]. This observation, along with similarities in functional properties, leads us to conclude that lactate transport in rabbit erythrocytes is mediated by the MCT1 monocarboxylate transporter isoform.
Poole
R C
RC
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
Halestrap
A P
AP
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D000595:Amino Acid Sequence; D000818:Animals; D002264:Carboxylic Acids / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004910:Erythrocyte Membrane / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D011817:Rabbits; D016415:Sequence Alignment
D002264:Carboxylic Acids; D002352:Carrier Proteins; D008565:Membrane Proteins; D027501:Monocarboxylic Acid Transporters; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid