title: Temperature dependence of solute transport and enzyme activities in hog renal brush border membrane vesicles.
abstract: The temperature dependence of sodium-dependent and sodium-independent D-glucose and phosphate uptake by renal brush border membrane vesicles has been studied under tracer exchange conditions. For sodium-dependent D-glucose and phosphate uptake, discontinuities in the Arrhenius plot were observed. The apparent activation energy for both processes increased at least 4-fold with decreasing temperature. The most striking change in the slope of the Arrhenius plot occurred between 12 and 15 degrees C. The sodium-independent uptake of D-glucose and phosphate showed a linear Arrhenius plot over the temperature range tested (35-5 degrees C). The behavior of the transport processes was compared to the temperature dependence of typical brush border membrane enzymes. Alkaline phosphatase as intrinsic membrane protein showed a nonlinear Arrhenius plot with a transition temperature at 12.4 degrees C. Aminopeptidase M, an extrinsic membrane protein exhibited a linear Arrhenius plot. These data indicate that the sodium-glucose and sodium-phosphate cotransport systems are intrinsic brush border membrane proteins, and that a change in membrane organization alters the activity of a variety of intrinsic membrane proteins simultaneously.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism; D007672:Kidney Cortex / Q000378:metabolism*; D007700:Kinetics; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D010710:Phosphates / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D012964:Sodium / Q000494:pharmacology*; D013045:Species Specificity; D013552:Swine; D013696:Temperature; D013816:Thermodynamics
chemical_list: D010710:Phosphates; D012964:Sodium; D005947:Glucose