title: Characterization of Na+/K+-ATPase from Xenopus laevis kidney. Preliminary results.
abstract: In Xenopus laevis, the renal Na+/K+-dependent ATPase is a very important enzyme involved in osmoregulatory processes and active transport. The enzyme was obtained from a microsome fraction purified by sucrose discontinuous gradient (10%, 15%, 29.4%) ultracentrifugation after SDS treatment, and concentrated in the denser layer. The assayed biochemical parameters and their values are: 1) Km (ATP): 0.24 mM; 2) K1/2 (Na+): 20.6 mM; 3) K1/2 (K+) 1.6 mM; 4) Ki (ouabain): 0.025 micrometer; 5) optimum pH: 7.2; 6) optimum temperature:" two peaks at 37 degrees C and 45 degrees C.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000302:isolation & purification / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism*
chemical_list: D010042:Ouabain; D000255:Adenosine Triphosphate; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium