| phosphatidylinositol 4,5-bisphosphate | <biochemistry> This is a molecule of phosphatidylinositol with two additional sites of phosphorylation. It is an important constituent of cell membrane phospholipids as well as a precursor of the second messengers, diacylglycerol and inositol 1,4,5-trisphosphate. Acronym: PIP2 (20 Sep 2002) |
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| phosphatidylinositol 4,5-bisphosphate kinase | <enzyme> Membrane-associated enzyme Registry number: EC 2.7.1.- Synonym: ptdins 4,5-p2 kinase, phosphatidylinositol 4,5-bisphosphate kinase, ptdins(4,5)p2 3oh-kinase (26 Jun 1999) |
| phosphatidylinositol 4,5-diphosphate | <biochemistry> A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase c, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (12 Dec 1998) |
| phosphatidylinositol 4-phosphate | <biochemistry> The intermediate in the biosynthesis of phosphatidylinositol 4,5-bisphosphate from phosphatidylinositol. (20 Sep 2002) |
| phosphatidylinositol 4-phosphate phosphatase | <enzyme> From human erythrocyte membranes Registry number: EC 3.1.3.- Synonym: ptdins-4p-phosphatase, phosphatidylinositol-4-phosphate monoesterase, ptdins4p monoesterase (26 Jun 1999) |
| phosphatidylinositol phosphates | <biochemistry> Phosphatidylinositols in which one or more alcohol group of the inositol has been substituted with a phosphate group. (12 Dec 1998) |
| phosphatidylinositol synthase | <enzyme> An enzyme that catalyses the reaction of CDP-diacylglycerol with inositol to form CMP and phosphatidylinositol; found in the endoplasmic reticulum. (20 Sep 2002) |
| phosphatidylinositol-3,4,5-trisphosphate 5-phosphatase | <enzyme> Hydrolyzes the 5-position phosphate of ptdins(3,4,5)p3 forming phosphatidylinositol-3,4-bisphosphate; an isoenzyme forms a complex with the p85/p110 form of pi 3-kinase Registry number: EC 3.1.3.- Synonym: ptdins(3,4,5)p3 5-phosphatase, pi(3,4,5)p3 5-pase (26 Jun 1999) |
| phosphatidylinositol-3-phosphatase | <enzyme> Hydrolyzes phosphatidylinositol 3-phosphate in nih 3t3 cells; specific as it has little or no activity on the monoester phosphates of ptdins(4)p, ptdins(4,5)p2, or inositol 1,3-bisphosphate; does not require added metal ions for activity and is maximally active in the presence of edta; inhibited by ca(2+), mg(2+),zn(2+), and the phosphatase inhibitor vo(3-)4 Registry number: EC 3.1.3.64 Synonym: phosphatidylinositol 3-phosphatase (26 Jun 1999) |
| phosphatidylinositol-ceramide phosphoinositol transferase | <enzyme> Involved in biosynthesis of inositol-containing sphingolipids; isolated from saccharomyces cerevisiae Registry number: EC 2.4.1.- Synonym: ipc synthase (26 Jun 1999) |
| phosphatidylinositols | <biochemistry> Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids. (12 Dec 1998) |
| phosphatidylserine | <biochemistry> The condensation product of phosphatidic acid and serine, found in biomembranes. It is an important minor species of phospholipid in membranes. Serine is attached to phosphatidic acid by a phosphodiester linkage. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids. Synthesis is from phosphatidylethanolamine by exchange of ethanolamine for serine. Distribution is asymmetric, as the molecule is only present on the cytoplasmic side of cellular membranes. It is negatively charged at physiological pH and interacts with divalent cations, involved in calcium dependent interactions of proteins with membranes (e.g. Protein kinase C). See: cephalin. (20 Sep 2002) |
| phosphaturia | <nephrology> The excessive discharge of phosphates in the urine. Origin: NL. See Phosphate, and Urine. (01 Mar 1998) |
| phosphene | <ophthalmology, physiology> Visual sensations arising from mechanical stimulation by pressure upon the eyeball when the lids are closed. It can also be produced by electrical stimulation of the eyeball. It is a luminous impression produced through excitation of the retina by some cause other than the impingement upon it of rays of light. Origin: Gr. Light + to show. (20 Sep 2002) |
| phosphide | <chemistry> A binary compound of phosphorus. Source: Websters Dictionary (01 Mar 1998) |