Abstract
Experiments were carried out to determine whether or not CDP-diacylglycerol:myo-inositol 3-phosphatidyltransferase (IT) activity (EC 2.7.8.11) could be detected in purified plasma-membrane fractions from WRK-1 rat mammary tumour cells. These cells have previously been shown to have a very active phosphoinositide cycle. Sucrose-density-gradient-purified plasma membranes contained no IT activity that could not be accounted for by endoplasmic-reticulum contamination. However, we also determined that the relative amount of IT activity in endoplasmic reticulum and plasma-membrane fractions could be altered by changing the concentration of detergent in the assay system.
Publication types
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Comparative Study
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Animals
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CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase
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Cell Fractionation
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Cell Membrane / enzymology*
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Centrifugation, Density Gradient
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Detergents / pharmacology
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Endoplasmic Reticulum / enzymology
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Kinetics
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Mammary Neoplasms, Experimental / enzymology*
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Membrane Proteins
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Phosphatidylinositols / metabolism*
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Phosphotransferases / metabolism*
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Rats
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Subcellular Fractions / drug effects
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Subcellular Fractions / enzymology
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Transferases (Other Substituted Phosphate Groups)*
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Tumor Cells, Cultured
Substances
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Detergents
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Membrane Proteins
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Phosphatidylinositols
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Phosphotransferases
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Transferases (Other Substituted Phosphate Groups)
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CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase
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Cdipt protein, rat