Detection of the membrane protein recognized by the kidney-specific alkylglucoside vector.
OBJECTIVE
Previously, we suggested that alkylglucoside can be an effective vector for renal-specific drug delivery (Suzuki et al., J. Pharmacol. Exp. Ther, 288:57-61, 1999). The purpose of the present study is to characterize the membrane protein which is recognized by this alkylglucoside.


METHODS
The binding of [125I] tyrosine conjugated with a octylthioglucoside (Glc-S-C8-[125I]Tyr) Glc-S-C8-[125I]Tyr to crude membrane fractions of kidney was determined. In addition, the membrane was cross-linked with this alkylglucoside and examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.


RESULTS
Glc-S-C8-[125I]Tyr was shown to have a specific binding site on the kidney membrane (Kd = 931 nM and Bmax = 987 pmol/mg protein). Cross-linking of the membrane with Glc-S-C8-[125I]Tyr resulted in the detection of a protein (Mr = 62,000), which was unaffected by reducing agents. The results of this cross-linking study were consistent with previous information on its localization and binding characteristics.


CONCLUSIONS
The kidney membrane protein, to which alkylglucoside binds in a specific manner, has a molecular weight of 62,000. Crosslinking is a useful tool for detecting this novel membrane protein in kidney.
Watanabe
Y
Y
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan.
Suzuki
H
H
Suzuki
K
K
Ando
T
T
Nakabayashi
S
S
Sugiyama
Y
Y
D000818:Animals; D002352:Carrier Proteins / Q000032:analysis*; D005960:Glucosides / Q000378:metabolism; D007668:Kidney / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D008970:Molecular Weight; D051381:Rats; D017207:Rats, Sprague-Dawley; D013329:Structure-Activity Relationship
D002352:Carrier Proteins; D005960:Glucosides; D008565:Membrane Proteins