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. 1981 Jul;68(1):18–22. doi: 10.1104/pp.68.1.18

Phosphatidylinositol Synthesis by a Mn2+-Dependent Exchange Enzyme in Castor Bean Endosperm 1

James C Sexton 1, Thomas S Moore Jr 1
PMCID: PMC425881  PMID: 16661866

Abstract

myo-Inositol is incorporated into phosphatidylinositol by an exchange reaction associated with the endoplasmic reticulum fraction isolated from post-germination castor bean endosperm. The reaction requires Mn2+, has a pH optimum of 8.0, an apparent Km for myo-inositol of 26 micromolar, and is stimulated about 15-fold by certain cytidine derivatives. The cytidine derivatives appear to be converted to CMP, which may be the only active stimulator. These optimal exchange reaction conditions, both with and without CMP, differ from those for cytidine-5′ -diphosphodiglyceride: myo-inositol transferase (EC 2.7.8), so the exchange does not appear to be a reversal of the transferase. This conclusion is augmented by the low rates of CDP-diglyceride formation from cytidine derivatives when compared to the high rate of myo-inositol incorporation into phosphatidylinositol in the presence of the same cytidine derivatives and identical reaction conditions.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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