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Activation of sarcoplasmic reticular Ca2+ transport ATPase by phosphorylation of an associated phosphatidylinositol.
Author(s) -
Varsanyi M.,
Tölle H.G.,
Heilmeyer M.G.,
Dawson R.M.,
Irvine R.F.
Publication year - 1983
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1983.tb01621.x
Subject(s) - phosphatidylinositol , phosphorylation , biochemistry , biology , enzyme , atpase , phosphate
Approximately 1 mol phosphatidylinositol phosphate is formed per mol isolated Ca2+ transport ATPase when the enzyme is incubated with ATP/Mg2+. The phosphorylation of this enzyme‐associated phosphatidylinositol represents the alkylphosphate formation described earlier. The phosphatidylinositol phosphate has been found in the hydrophobic core of the enzyme. A complex of phosphatidylinositol phosphate with protein can be extracted with acidic chloroform/methanol. The protein behaves like proteolipid during chromatography on Sephadex LH 60 and binds the radioactively labelled phosphatidylinositol phosphate. The phosphorylation of approximately 1 mol phosphatidylinositol per 100,000 g protein correlates with an enhancement of the Ca2+ transport ATPase activity which is due to an approximately 7‐fold enhanced affinity for Ca2+ and an approximately 2‐fold enhanced maximal turnover.