Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alkaline phosphatases (APases, EC 3.1.3.1) are ecto-enzymes bound to cell membranes by a phosphatidyl-inositol anchor. We have previously shown that APase is present on activated murine B cells and its expression correlates with the process of B cell differentiation into immunoglobulin secretion. Recently, a monoclonal antibody (mAb), G-5-2, that recognizes a 76-kDa molecule preferentially expressed on the surface of pre-B and plasma cells (PB76) was described. Some features shared by APase and PB76 differentiation antigen suggest that the G-5-2 mAb might be specific for lymphocyte APase. Here, we have analyzed this possibility and found an absolute correlation between PB76 expression in cells and their APase activity. Although PB76 has been described as a B cell-restricted marker, PB76 is also expressed on some T cells, such as the YAC-1 T cell lymphoma, that are known to bear APase. Treatment of YAC-1 cells with phosphatidylinositol-specific phospholipase C resulted in a quantitatively correlated removal of both APase and PB76 antigens. Moreover, we demonstrate that PB76 antigen has APase activity using an enzyme-antigen immunoassay with the G-5-2 mAb. We conclude that PB76 and lymphocyte APase are one and the same antigen.
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PMID:Identity of PB76 differentiation antigen and lymphocyte alkaline phosphatase. 234 70

Decay-accelerating factor (DAF) is an integral membrane protein that inhibits amplification of the complement cascade on the cell surface. We and other investigators have shown that DAF is part of a newly characterized family of proteins that are anchored to the cell membrane by phosphatidylinositol (PI). The group includes the variant surface glycoprotein (VSG) of African trypanosomes, the p63 protein of Leishmania, acetylcholinesterase (AChE), alkaline phosphatase, Thy-1, 5'-nucleotidase, and RT6.2--an alloantigen from rat T cells. The structure of the membrane anchor has been best characterized for VSG, but chemical studies of the membrane anchors of AChE and Thy-1 suggest that similar glycolipid moieties anchor these proteins to the cell surface. In the VSG, the membrane anchor consists of an ethanolamine linked covalently to an oligosaccharide and glucosamine; the entire complex is anchored to the cell membrane by PI. Immunologically, this glycolipid defines an epitope, the cross-reacting determinant (CRD), that is only revealed after removal of the diacyl glycerol anchor by a phospholipase C. By Western blotting, we show here that DAF-S (DAF released from the membrane by PI-specific phospholipase C [PIPLC]) also contains CRD. Using a newly developed immunoradiometric assay (IRMA) in which the solid-phase capturing antibody is a monoclonal antibody to DAF and the second antibody is anti-CRD, we have been able to quantitate DAF-S. By IRMA, we show that the reaction between anti-CRD and DAF-S is specific, since the binding is competitively inhibited only by the soluble form of the VSG. These observations further support the concept that the glycolipid anchors of this new family of proteins have similar structures. DAF is also found as a soluble protein in various tissue fluids as well as in Hela cell supernatants. No evidence for the presence of the CRD epitope was found on these proteins, suggesting that these forms of DAF are not released from the surface of cells by endogenous phospholipases.
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PMID:Decay-accelerating factor (DAF) shares a common carbohydrate determinant with the variant surface glycoprotein (VSG) of the African Trypanosoma brucei. 243 27

The mouse lymphocyte surface alloantigen, Ly-31, defined by monoclonal antibody N1.10 (IgG2b,k) and controlled by a gene locus closely linked to the Akp-2 locus on chromosome 4, was biochemically investigated. By employing a quantitative immunoassay system, it was found that the Ly-31.1-specific antibody detected an allotypic determinant of mouse alkaline phosphatase. Ly-31.1, i.e., mouse alkaline phosphatase, was expressed predominantly in kidney and bone and was also detected in placenta, lung, and testis. Concerning tumor cell lines, they varied in the amount of antigen present, with both T and B lymphoid lineages selectively possessing the antigen. In normal lymphoid tissues, lesser amounts of antigen were detected. The binding of mouse alkaline phosphatase to Ly-31.1-specific monoclonal antibodies was specific in nature. The Ly-31.1 antigen was immunoprecipitated from the lysates of surface-radiolabeled YAC-1 moloney leukemia cells, and appeared as a single band of about 78,000 under both reduced and nonreduced conditions on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Furthermore, treatment of tumor cell lines with phosphatidylinositol-specific-phospholipase C resulted in the removal of Ly-31 antigen from the cell surface. These results suggest that a gene cluster containing the Ly-31 and Akp-2 loci which control the alkaline phosphatase is formed on mouse chromosome 4. The Ly-31 antigen is the first enzyme demonstrated to be a lymphocyte surface alloantigen.
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PMID:Mouse Ly-31.1 is an alloantigenic determinant of alkaline phosphatase predominantly expressed in the kidney and bone. 246 81

Daily s.c. injection of gentamicin at either 100 mg/kg for 4 days or 60 mg/kg for 2 weeks produced nephrotoxicity in the adult rat as judged by an increase in urinary excretion of beta-galactosidase, beta-glucuronidase and beta-N-acetylglucosaminidase. The observed enzymuria was associated with significant elevation in total renal phospholipid, phosphatidylinositol, phosphatidylcholine and phosphatidylserine. In addition, gentamicin decreased the activities of renal cortical Na+-K+-adenosine triphosphatase, alkaline phosphatase as well as phospholipase C. Pyridoxal-5'-phosphate (250 mg/kg/day) administered i.p. for 4 or 14 days did not markedly alter the metabolic markers of kidney function. In rats simultaneously given pyridoxal-5'-phosphate and gentamicin for 4 days the vitamin failed to prevent either the antibiotic-induced decrease in renal phospholipase C and alkaline phosphatase or the increase in total renal phospholipid, phosphatidylinositol, phosphatidylcholine and phosphatidylserine. However, simultaneous pyridoxal-5'-phosphate and aminoglycoside treatment for 2 weeks proved effective in blockade of the gentamicin-induced kidney phospholipidosis, elevation in urinary beta-galactosidase, beta-glucuronidase and beta-N-acetylglucosaminidase, as well as reduction in renal phospholipase C and alkaline phosphatase. The gentamicin-induced nephrotoxicity was associated with a decrease in renal pyridoxal-5'-phosphate levels. In the simultaneous 4-day-treated rat the renal concentration of pyridoxal-5'-phosphate returned to approximate control values, whereas after 2 weeks the level of vitamin B6 was approximately 2-fold higher than control. Although pyridoxal-5'-phosphate in the simultaneous group lowered kidney gentamicin content by 40% after 4 or 14 days, protection from aminoglycoside-induced nephrotoxicity was apparent only after 2 weeks in our study.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of gentamicin-induced nephrotoxicity by pyridoxal-5'-phosphate in the rat. 249 42

The involvement of inositol lipid metabolism in agonist-mediated Ca2+ signaling by Ins 1,4,5-P3 has become firmly established. Recent advances have led to a better understanding of the proteins associated with signal transduction in the plasma membrane. A number of specific receptors (G proteins, phospholipases and inositol lipid kinases) have now been purified and characterized. An Ins 1,4,5-P3 receptor has also been purified which is presumably involved in mediating Ca2+ efflux from intracellular stores. The morphological site of the hormone-sensitive Ca2+ pool has been tentatively identified as discrete, specialized intracellular structures (calciosomes), but further studies are required to demonstrate that these contain Ins 1,4,5-P3-gated Ca2+ channels and their possible functional relationship to the plasma membrane. Receptor occupancy by Ca2+ mobilizing agonists also stimulates Ca2+ entry into the cell, but the mechanism for activation of voltage insensitive Ca2+ channels and the possible involvement of Ins 1,4,5-P3, Ins 1,3,4,5-P4 and/or G proteins in this process has not been established. The Ca2+ signaling pathway is subject to multisite feedback regulation by Ca2+ itself and by a diacylglycerol-mediated activation of protein kinase C. Potential sites for Ca2+ interaction are displacement of Ins 1,4,5-P3 from its receptor by a Ca2+-dependent mechanism, promotion of Ins 1,3,4,5-P4 formation by the Ca2+/calmodulin-regulated Ins 1,4,5-P3 3-kinase, and efflux of Ca2+ from the cell or sequestration into intracellular Ca2+ stores by Ca2+/calmodulin-regulated Ca2+-ATPases. Protein kinase C activation potentially affects the rate of generation of Ins 1,4,5-P3 by negative feedback to the receptor-G protein-phospholipase C transduction system and possibly also the rate of Ins 1,4,5-P3 degradation by activation of an inositol polyphosphate 5-phosphomonoesterase. It may also attenuate the Ca2+ transient directly by increasing the activity of Ca2+-ATPases associated with the plasma membrane and the endoplasmic reticulum. Cell-to-cell heterogeneity in the relative control strengths of these different mechanisms may explain the differences in the Ca2+ signal in different tissues and even in different cells within a population. The ability of Ca2+ and protein kinase C to provide negative feedback at various points in the signal transduction pathway suggests that a complex mechanism involving multiple feedback loops is likely to regulate the generation of Ca2+ oscillations seen in some cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hormone effects on cellular Ca2+ fluxes. 249 41

In Pseudomonas aeruginosa, choline or betaine employed as the sole carbon and nitrogen source in a high phosphate medium induced a phospholipase C and an acid phosphatase activity but not an alkaline phosphatase activity. The P. aeruginosa strain utilized in this work does not possess a constitutive phospholipase C, since under culture conditions identical to those utilized by other authors (J. Bacteriol. 93, 670-674 (1967) and J. Bacteriol. 150, 730-738 (1982), our phospholipase C proved to be an inorganic phosphate-repressible enzyme. These findings enable us to conclude that although the phosphate control for the synthesis of phospholipase C may exist, it is expressed only under certain favorable culture conditions.
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PMID:Choline and betaine as inducer agents of Pseudomonas aeruginosa phospholipase C activity in high phosphate medium. 249 57

Bacillus cereus secretes three different phospholipases C. We studied the effect of Pi levels in the growth medium on the production of these exoenzymes. Production of both phosphatidylcholine-preferring phospholipase C and sphingomyelinase C was repressed by Pi in the growth medium, whereas production of phosphatidylinositol phospholipase C was unaffected. We also found that B. cereus secretes a phosphate-repressed alkaline phosphatase activity. Together with a previously reported highly efficient, active uptake system for Pi, these three phosphate-repressed exoenzyme activities seem to be part of a phosphate retrieval mechanism that operates under growth-limiting concentrations of Pi. In natural soil systems, which are the natural habitats of B. cereus, the scarcity of Pi is the major growth-limiting factor. A phosphate-repressed metalloprotease activity was also detected in culture supernatants of B. cereus. It is unclear whether this exoenzyme activity also participates in the proposed phosphate-scavenging system.
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PMID:Apparent phosphate retrieval system in Bacillus cereus. 250 29

Daily subcutaneous administration of 20 or 100 mg/kg gentamicin for 4 days significantly decreased pyridoxal-5'-phosphate and lysosomal specific phosphatidylinositol-phospholipase C (PI-PLC) in newborn rat kidney. The fall in PI-PLC was associated with an elevation in renal phosphatidylinositol, phosphatidylserine, and phosphatidylcholine. The 100 mg/kg gentamicin dose also produced a rise in renal sphingomyelin, phosphatidylethanolamine, phosphatidylglycerol, and total phospholipid (TPL) accompanied by inhibition in the activities of Na+,K+-ATPase and alkaline phosphatase. In contrast, daily intraperitoneal injection of 100 mg/kg vancomycin for 4 days failed to markedly alter renal metabolic parameters. However, the 500 mg/kg vancomycin dose increased kidney weight, TPL, and all individual phospholipid class concentrations accompanied by inhibition of lysosomal specific PI-PLC activity and reduced pyridoxal-5'-phosphate levels. Simultaneous administration of 20 mg/kg gentamicin with either vancomycin dose resulted in renal alterations similar to those produced by gentamicin alone. Concurrent treatment with 100 mg/kg aminoglycoside and either vancomycin dose produced changes in kidney which were similar to those produced by gentamicin alone, except for a synergistic rise in PI as well as a greater fall in alkaline phosphatase and pyridoxal-5'-phosphate. Surprisingly, the concentration of gentamicin and vancomycin was less in newborn kidneys of rats receiving a simultaneous high dose of vancomycin and aminoglycoside treatment compared to levels found in animals given either antibiotic separately. The lack of potentiation of nephrotoxicity in newborns administered a combination of vancomycin and gentamicin may be due to decreased accumulation of either antibiotic in kidney.
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PMID:Gentamicin-induced renal metabolic alterations in newborn rat kidney: lack of potentiation by vancomycin. 252 10

Heparan sulfate proteoglycans (HSPG) of rat liver are associated with the plasma membrane in a hydrophobic intrinsic and a hydrophilic extrinsic form. We were interested in determining whether or not these two forms could be detected in the Golgi apparatus, the subcellular site of addition of oligosaccharides and sulfate to HSPG. In vivo and in vitro radiolabeled HSPG from rat liver Golgi apparatus membranes could only be solubilized with detergents that disrupt the membrane lipid bilayer, suggesting that they are solely associated via hydrophobic interactions. Both forms of HSPG were detected in plasma membranes of rat liver and isolated rat hepatocytes. The detergent-solubilized HSPG bound to octyl-Sepharose columns, whereas the hydrophilic form did not; this latter form, however, was released from the membrane by heparin. The hydrophobic anchor of HSPG in the Golgi and plasma membranes was insensitive to treatment with phosphatidylinositol-specific phospholipase C under conditions in which alkaline phosphatase was sensitive; this suggests that the hydrophobic anchor of HSPG is the core protein itself. Preliminary experiments suggest that the subcellular site of processing of the hydrophobic to the hydrophilic form of HSPG is the plasma membrane. A specific processing activity, probably a protease of the plasma membrane not present in serum or the endoplasmic reticulum membrane, converted hydrophobic HSPG of the Golgi membrane to the hydrophilic form. In addition, pulse-chase experiments with [35S]Na2SO4 in rats demonstrated that at short times, the bulk of the radiolabeled cellular HSPG was in the Golgi apparatus; later on, the bulk of the radioactivity was found in the plasma membrane, the only subcellular site where the hydrophilic form of HSPG was detected.
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PMID:Differential association of rat liver heparan sulfate proteoglycans in membranes of the Golgi apparatus and the plasma membrane. 252 26

Since our previous experiments suggested that glycosylation-inhibiting factor (GIF) is a phosphorylated derivative of a phospholipase inhibitory protein, we determined whether other well-known phospholipase inhibitors may have similar biological activities. The results showed that phospholipase A2 (PLA2) inhibitors, such as recombinant human lipocortin I and ONO-RS-082, could switch T cell hybridoma 12H5 cells from the formation of glycosylated IgE-binding factors (IgE-BF) to the formation of unglycosylated IgE-BF, whereas neomycin, a phospholipase C inhibitor, failed to affect the nature of IgE-BF formed by the cells. The minimum concentrations of lipocortin I and ONO-RS-082 required for switching the 12H5 cells to the formation of unglycosylated IgE-BF were comparable to or less than IC50 of the inhibitors for PLA2. The ability of partially purified GIF to switch the 12H5 cells to the formation of unglycosylated IgE-BF was markedly enhanced by treatment of the preparation with alkaline phosphatase. It was also found that lipocortin I and ONO-RS-082, but not neomycin, facilitated the generation of GIF-producing T cells. When spleen cells of ovalbumin (OVA)-primed BDF1 mice were stimulated with homologous antigen and the activated T cells were propagated by recombinant IL-2 in the presence of GIF, lipocortin I, or ONO-RS-082, T cells obtained in the cultures constitutively produced their own GIF. Antigenic stimulation of the T cells induced the formation of unglycosylated IgE-BF and GIF with an affinity for OVA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of phospholipase A2 inhibitors on mouse T lymphocytes. I. Phospholipase A2 inhibitors exert similar immunological activities as glycosylation inhibiting factor. 253 36


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