Radiation inactivation studies of the renal brush-border membrane phlorizin-binding protein.
Renal brush-border membrane vesicles were irradiated in the frozen state with a high energy electron beam. The integral membrane proteins, alkaline phosphatase and 5'-nucleotidase, each showed a single exponential loss of activity with radiation dose, indicating target sizes of 67,000 and 58,000 daltons, respectively. Inactivation of sodium-dependent phlorizin binding to the brush-border membrane D-glucose transporter was more complex. One-half of the phlorizin binding sites were lost after even the smallest doses of radiation suggestive of large functional units (greater than 4 X 10(6) daltons) for a subpopulation of phlorizin binding proteins. The remaining sites behaved as a single radiation target of 110,000 +/- 8,000 daltons and retained the kinetic characteristics commonly associated with phlorizin binding to the glucose transporter. Thus, the data are consistent with the assignment of a molecular weight of 110,000 to the phlorizin binding moiety of the brush-border membrane D-glucose transport protein.
D015720:5'-Nucleotidase; D000818:Animals; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000528:radiation effects*; D002462:Cell Membrane / Q000528:radiation effects*; D007672:Kidney Cortex / Q000378:metabolism / Q000528:radiation effects*; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism / Q000528:radiation effects*; D008970:Molecular Weight; D009708:Nucleotidases / Q000378:metabolism / Q000528:radiation effects; D011817:Rabbits
D002352:Carrier Proteins; C035685:phlorizin-binding protein, mammal; D009708:Nucleotidases; D015720:5'-Nucleotidase