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.
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
R C
RC
Poole
A P
AP
Halestrap
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