Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel bovine spleen phosphoinositide-specific phospholipase C (PLC) has been identified with respect to immunoreactivity with four independent antibodies against each of the PLC isoenzymes, and purified to near homogeneity by sequential column chromatography. Spleen contains three of the isoenzymes: two different gamma-types [gamma 1 and gamma 2, originally named as PLC-gamma [Rhee, Suh, Ryu & Lee (1989) Science 244, 546-550] and PLC-IV [Emori, Homma, Sorimachi, Kawasaki, Nakanishi, Suzuki & Takenawa (1989) J. Biol. Chem. 264, 21885-21890] respectively] and delta-type of the enzyme, but PLC-gamma 1 is separated from the PLC-gamma 2 pool by the first DEAE-cellulose column chromatography. Subsequently, PLC-delta is dissociated on the third heparin-Sepharose column chromatography. The purified enzyme has a molecular mass of 145 kDa on SDS/polyacrylamide-gel electrophoresis and a specific activity of 12.8 mumol/min per mg with phosphatidylinositol 4,5-bisphosphate as substrate. This enzyme activity is dependent on Ca2+ for hydrolysis of all these phosphoinositides. None of the other phospholipids examined could be its substrate at any concentration of Ca2+. The optimal pH of the enzyme is slightly acidic (pH 5.0-6.5).
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PMID:Isolation and characterization of a gamma-type phosphoinositide-specific phospholipase C (PLC-gamma 2). 216 90

Two isozymes of phosphoinositide-specific phospholipase C were isolated and purified from salt-washed rabbit brain membranes. The membranes were extensively washed with isotonic, hypertonic and hypotonic buffers prior to solubilization with sodium cholate. Two isozymes (PLC-IV and PLC-beta m) were purified by a combination of DEAE-Sephacel, AH-Sepharose, heparin-Sepharose, AcA-34 gel filtration and mono-Q FPLC chromatographies. The major activity (PLC-beta m) was purified to homogeneity and had an estimated molecular weight of 155,000 on sodium-dodecyl sulfate-polyacrylamide gels (SDS-PAGE). This isozyme was immunologically identified as PLC-beta, an isozyme previously characterized in bovine brain cytosol and 2 M KCl membrane extracts. A second isozyme, PLC-IV, was immunologically distinct from PLC-beta and PLC-gamma and was purified to a stage where three protein bands (Mr 66,000, 61,000 and 54,000) on SDS-PAGE correlated with enzyme activity. The catalytic properties of the isozymes were studied and found to be very similar. The specific activities for PIP2 were greater than those obtained when PI was used. Both PLC-IV and PLC-beta m were Ca2(+)-dependent; near maximal stimulation for PI and PIP2 hydrolysis was observed at 0.5 microM free Ca2+. Sodium pyrophosphate and sodium fluoride stimulated phospholipase C activity of both isozymes. Polyclonal antibodies raised against PLC-beta m were able to inhibit carbachol and GTP gamma S stimulated phospholipase C activity in 2 M KCl washed rabbit cortical membranes. This suggests that in rabbit brain muscarinic cholinergic stimulation regulates PLC-beta m.
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PMID:Purification and characterization of PLC-beta m, a muscarinic cholinergic regulated phospholipase C from rabbit brain membrane. 216 89

The mRNA levels for four types of inositol phospholipid-specific phospholipase C (PLC) in various tissues and cell cultures have been studied by Northern analysis using cDNA probes for PLC isozyme I, II, and III [Sue, P.-G., Ryu, S.H., Moon, K.H., Sue, H.W., and Rhee, S.G. (1988) Proc. Natl. Acad. Sci. USA 85, 5419-5423 and Cell 54, 161-169], and the recently identified isozyme IV. All four types are ubiquitously expressed in rat tissues, but the levels of the mRNAs vary among tissues and cell lines. PLC-I mRNA levels are extremely high in brain and rat C6 glioma cells with lower levels in other tissues tested. PLC-II and -III have a more widespread distribution, with relatively high levels in brain, lung, spleen, thymus, and testis in the case of PLC-II, and in skeletal muscle, spleen, and testis for PLC-III. PLC-II and -III mRNAs were also detected in all cell lines examined except human promyelocytic HL60 cells. PLC-IV mRNA levels are extraordinarily high in spleen and HL60 cells. These results indicate that rat C6 glioma cells, together with most rat tissues, contain all four PLC isozymes. Other cultured cell types examined also contain two or three PLC isozymes except for HL60 cells, which contain only PLC-IV. The concomitant expression of PLC isozymes in cultured cells suggests a diverse function for PLC isozymes in single cells.
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PMID:Tissue- and cell type-specific expression of mRNAs for four types of inositol phospholipid-specific phospholipase C. 255 17