Molecular size of the renal sodium/phosphate symporter in native and reconstituted systems.
The size of the renal sodium/phosphate symporter was estimated with the radiation inactivation technique in isolated bovine brush border membrane vesicles and after reconstitution in proteoliposomes. The functional unit of the native phosphate carrier had a radiation inactivation size of 172 +/- 17 kDa. Identical values were obtained for the reconstituted carrier whether it was irradiated before or after the formation of the proteoliposomes (161 +/- 9 and 159 +/- 11 kDa, respectively). The sodium-independent uptake of phosphate was not affected significantly by radiation doses up to 10 Mrad. This activity is therefore not due to the reconstitution of a large phosphate-binding protein such as alkaline phosphatase. Furthermore, bromotetramisole, a specific inhibitor of phosphate binding to this enzyme, had no significant effect on the uptake of phosphate by the proteoliposomes.
Delisle
M C
MC
Département de chimie-biochemie, Université du Québec à Montréal, Canada.
Vachon
V
V
Giroux
S
S
Potier
M
M
Laprade
R
R
Béliveau
R
R
D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D007668:Kidney / Q000378:metabolism*; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism; D011510:Proteolipids; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D013773:Tetramisole / Q000031:analogs & derivatives / Q000494:pharmacology
D002352:Carrier Proteins; D011510:Proteolipids; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; C020485:proteoliposomes; C006226:4-bromotetramisole; D013773:Tetramisole