Phosphatidylinositol Synthase of Tetrahymena: Inositol Isomers as Substrates in Phosphatidylinositol Biosynthesis and Headgroup Exchange Reactions
| Autor: | Tanya A. Lansley, Phillip E. Ryals, Bridget M. Riggs |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Cytidine monophosphate
Magnesium Chloride Biology Phosphatidylinositols Microbiology Substrate Specificity chemistry.chemical_compound Chlorides Biosynthesis Transferases Cytidine Monophosphate Animals Inositol Phosphatidylinositol Molecular Structure ATP synthase Temperature Tetrahymena Stereoisomerism Hydrogen-Ion Concentration CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase biology.organism_classification Enzyme Activation Manganese Compounds chemistry Biochemistry Second messenger system biology.protein lipids (amino acids peptides and proteins) scyllo-Inositol |
| Zdroj: | The Journal of Eukaryotic Microbiology. 54:119-124 |
| ISSN: | 1550-7408 1066-5234 |
| DOI: | 10.1111/j.1550-7408.2007.00242.x |
| Popis: | Phosphatidylinositol (PtdIns) synthase in microsomal fractions derived from Tetrahymena vorax was studied to determine its activity requirements. The suitability of inositol isomers as substrates for the synthase and in headgroup exchange reactions also was investigated. Tetrahymena PtdIn synthase activity was optimum in the presence of 2 mM MgCl2 plus 2 mM MnCl2, a pH of 7.8, and a temperature of 30 degrees C. The enzyme retained approximately 80% of its activity after incubation at 70 degrees C for 10 min. PtdIns headgroup exchange activity was maximal in the presence of cytidine monophosphate. By following either the accumulation of radiolabeled reaction products or the loss of radiolabel from precursors, each of the inositol isomers tested appeared to serve as substrates for both the PtdIns synthase and PtdIns:inositol phosphatidyl transferase activities. In each case, myo-inositol and scyllo-inositol were the preferred substrates. The data suggest two routes for the formation of phosphatidyl-non-myo-inositols in Tetrahymena and the potential for the production of novel, non-myo-inositol-containing second messengers. |
| Databáze: | OpenAIRE |
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