Unknown

Dataset Information

0

Some properties of the Ca2+-stimulated ATPase of a rat liver microsomal fraction.


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.

SUBMITTER: Dawson AP 

PROVIDER: S-EPMC1154238 | biostudies-other | 1983 Feb

REPOSITORIES: biostudies-other

Similar Datasets

| S-EPMC1158551 | biostudies-other
| S-EPMC1146567 | biostudies-other
| S-EPMC1147047 | biostudies-other
| S-EPMC1183864 | biostudies-other
| S-EPMC1146712 | biostudies-other
| S-EPMC1177492 | biostudies-other
| S-EPMC1164521 | biostudies-other
| S-EPMC7693334 | biostudies-literature
| S-EPMC1177245 | biostudies-other
| S-EPMC1152211 | biostudies-other