Some properties of the Ca2+-stimulated ATPase of a rat liver microsomal fraction
- 15 February 1983
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 210 (2) , 405-410
- https://doi.org/10.1042/bj2100405
Abstract
1. The heavy microsomal fraction from rat liver apparently has very little Ca2+-stimulated ATPase activity, although it has an active, ATP-driven Ca2+ accumulation system. 2. The addition of ionophore A23187 to the ATPase assay, to allow continuous Ca2+ recycling during the assay time, reveals the presence of a substantial Ca2+-stimulated ATPase with Vmax. 160 nmol of Pi/10 min per mg of protein and Km for Ca2+ 0.19 microM. 3. The Ca2+-stimulated ATPase, but not the basal Mg2+-stimulated ATPase, is potently inhibited by orthovanadate. Both the Ca2+-stimulated ATPase and the vanadate inhibition are enhanced by the presence of Mg2+. 4. Ca2+-stimulated ATPase activity is not responsive to calmodulin or the calmodulin antagonist trifluoperazine.This publication has 18 references indexed in Scilit:
- The Ca2+-pumping ATPase of heart sarcolemma. Characterization, calmodulin dependence, and partial purification.Journal of Biological Chemistry, 1981
- CALMODULIN IN NATURAL AND RECONSTITUTED CALCIUM TRANSPORTING SYSTEMS*Annals of the New York Academy of Sciences, 1980
- Inhibition of red cell Ca2+-ATPase by vanadateBiochimica et Biophysica Acta (BBA) - Biomembranes, 1980
- Characterization of the hormone-sensitive Ca2+ uptake activity of the hepatic endoplasmic reticulumBiochimica et Biophysica Acta (BBA) - General Subjects, 1980
- Effects of potassium on vanadate inhibition of sarcoplasmic reticulum Ca2+-ATPase from dog cardiac and rabbit skeletal muscleBiochemical and Biophysical Research Communications, 1979
- Properties of energy-dependent calcium transport by rat liver microsomal fraction as revealed by initial-rate measurementsBiochemical Journal, 1978
- Isolation of a potent (Na -K) stimulated ATPase inhibitor from striated muscleBiochemistry, 1977
- Partial purification of the Ca2+-Mg2+ ATPase activator from human erythrocytes: Its similarity to the activator of 3′:5′ — cyclic nucleotide phosphodiesteraseBiochemical and Biophysical Research Communications, 1977
- Phosphodiesterase protein activator mimics red blood cell cytoplasmic activator of (Ca2+-Mg2+)ATPaseBiochemical and Biophysical Research Communications, 1977
- Energy-dependent calcium sequestration activity in rat liver microsomes.Journal of Biological Chemistry, 1975