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)

Resting chondrocytes do not usually undergo differentiation to the hypertrophic stage and calcification. However, incubating these cells with concanavalin A resulted in 10-100-fold increases in alkaline phosphatase activity, binding of 1,25(OH)2-vitamin D3, type X collagen synthesis, 45Ca incorporation into insoluble material, and calcium content. On the other hand, other lectins tested (including wheat germ agglutinin, lentil lectin, pea lectin, phytohemagglutinin-L, and phytohemagglutinin-E) marginally affected alkaline phosphatase activity, although they activate lymphocytes. Methylmannoside reversed the effect of concanavalin A on alkaline phosphatase within 48 h. Concanavalin A did not increase alkaline phosphatase activity in articular chondrocyte cultures. In resting chondrocyte cultures, succinyl concanavalin A was as potent as concanavalin A in increasing alkaline phosphatase activity, the incorporation of [35S]sulfate, D-[3H]glucosamine, and [3H]serine into proteoglycans, and the incorporation of [3H]serine into protein, although concanavalin A, but not succinyl concanavalin A, induced a rapid change in the shape of the cells from flat to spherical. These findings suggest that concanavalin A induces a switch from the resting, to the growth-plate stage, and that this action of concanavalin A is not secondary to changes in the cytoskeleton. Chondrocytes exposed to concanavalin A may be useful as a novel model of endochondral bone formation.
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PMID:Effects of concanavalin A on chondrocyte hypertrophy and matrix calcification. 906 48

myo-Inositol has been believed to be a sole inositol isomer existing in phosphatidylinositol (PI) and related derivatives. In this experiment, chiro-inositol, an inositol isomer other than myo-inositol, was identified in hydrolytic products from several GPI-anchored proteins. The chiro-inositol contents in several different GPI-anchored proteins including 5'-nucleotidase of bovine liver and alkaline phosphatase of mouse NS-1 varied with hydrolytic conditions of these GPI anchor. Isomerization of 20-60% of myo-inositol occurred on the hydrolysis in 6 N HCl solution. Under the hydrolytic conditions of a HCl gas stream in place of solution, however, isomerization was very low (less than 0.1%). Even in the hydrolysis under HCl gas stream, existence of CNBr accelerated the isomerization of inositol in GPI up to 70-95%. In the hydrolysis of phosphatidylinositol or myo-inositol 1-phosphate, however, a significant amount of chiro-inositol was not detected in 6 N HCl solution or in the existence of CNBr under the HCl stream. These facts indicated that isomerization occurred during the hydrolysis of the GPI anchor, when myo-inositol is substituted by glucosamine at 6-OH and is substituted by phosphate at 1-OH. It also suggested that the former identification of chiro-inositol in GPI structure in the various reports might be due to isomerization.
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PMID:Identification of chiro-inositol and its formation by isomerization of myo-inositol during hydrolysis of glycosylphosphatidylinositol-anchored proteins. 918 25

Alkaline phosphatase, a marker of differentiation in the human alveolar adenocarcinoma cell line A549, is inducible by conditioned medium from lung fibroblasts and by cytokines including oncostatin M and interleukin 6, but only in the presence of a glucocorticoid, dexamethasone. Dexamethasone was shown to induce incorporation of [3H]glucosamine into three fractions of medium and cell trypsinate from subconfluent A549 cells, eluting from DEAE ion-exchange chromatography. The first peak did not correspond to any of the unlabelled glycosaminoglycans and was not characterized further. Induction was seen in two other peaks, corresponding to hyaluronic acid and heparan sulphate. Of these, heparan sulphate, eluting as one well-defined peak (referred to as HS1) and another of lower activity and less well defined (HS2), was selected as the most likely to interact with growth factors and cytokines and was isolated from the eluate, concentrated and desalted, and used in alkaline phosphatase induction experiments in place of dexamethasone. HS1 isolated from the medium (HS1m) of subconfluent A549 cells was shown to replace dexamethasone in induction experiments with fibroblast-conditioned medium, oncostatin M and interleukin 6. HS1 from the cell trypsinate and HS2 from the medium and trypsinate were inactive. As the activity of HS1m could be abolished by heparinase and heparitinase but not by chondroitinase ABC, it was concluded that HS1m was a fraction of heparan sulphate involved in the regulation of paracrine growth factor activity in lung fibroblast-conditioned medium, and in the regulation of other growth factors with potential roles in the paracrine control of cell differentiation.
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PMID:Activation of paracrine growth factors by heparan sulphate induced by glucocorticoid in A549 lung carcinoma cells. 925 93

Pseudomonas putida GR12-2R3 promotes the emergence and growth of diverse plant species. Analyses of TnphoA insertion mutations are revealing bacterial characteristics pertinent to the plant-microbe interaction. Pseudomonas putida PG269 is a TnphoA insertion derivative of GR12-2R3 that expresses canola seed exudate-inducible alkaline phosphatase (PhoA) activity. It promoted the growth of canola roots, as well as strain GR12-2R3, and outgrew its parent when they were cocultured in the presence of canola roots or in liquid seed exudate medium. (In contrast, mutant PG126 failed to promote canola root growth and was outgrown by its parent strain.) The PhoA activity of strain PG269 was induced by glucosamine and other sugars; glucosamine inhibited the growth of strain GR12-2R3 and stimulated the growth of strain PG269. Strain PG269 contained two TnphoA insertions: seiA1::TnphoA and seiB1::TnphoA. Strain PG312, which contained only insertion seiA1::TnphoA, shared all aspects of the PG269 phenotype, except the ability to outcompete strain GR12-2R3 during coculture. Insertion seiA1::TnphoA interrupted an open reading frame related in sequence to members of the MalF family of sugar transporter subunits. The PhoA-inducing fraction of canola seed exudate was hydrophilic, low in molecular weight, and heat stable. It cochromatographed with basic amino acids and amino sugars, and was inactivated by strains GR12-2R3 and PG269. Gene seiA may encode a subunit of an ABC transporter with broad specificity for glucose and related sugars whose expression can be induced by exudate sugars.
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PMID:Bacterial genetic loci implicated in the Pseudomonas putida GR12-2R3--canola mutualism: identification of an exudate-inducible sugar transporter. 933 44

The results reported here show that sodium fluoride (NaF) at low concentration (up to 10 microM) increased four times the proliferation rate of avian osteoblasts in culture. Also NaF increases, in a concentration dependent manner, 10 times the alkaline phosphatase activity. However, NaF decreased the incorporation of 35S-sulfate into proteoglycans (PGs) synthesized by osteoblasts (60-65%). Also, we observed that PGs synthesized in the presence of NaF (50 microM) exhibited a higher sensitivity to chondroitinase ABC than PGs synthesized by osteoblasts in the absence of NaF, suggesting an increase in the chondroitin sulfate moieties associated with the core protein of PGs. The modification of glycosaminoglycan (GAG) chains composition was evidenced also by change in the mean charge density of the PGs observed by ion exchange chromatography. Since the ratio of 35SO4/3H-glucosamine incorporated into PGs was similar in the presence and in the absence of NaF (8.2 and 7, respectively), it is not possible to explain differences in mean charge density by changes in the sulfation extent of PGs. No differences were observed in the hydrodynamic size of PG synthesized in the presence of NaF, nor in the hydrodynamic size of the GAG chains. According to these results, we speculate that the stimulatory effect of fluoride on bone mineralization may be mediated, in part, by the changes in the rate of synthesis or in the structural characteristics of bone PGs. The changes produced by fluoride in PGs suggest that these molecules play an inhibitory role in the bone mineralization process.
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PMID:Sodium fluoride induces changes on proteoglycans synthesized by avian osteoblasts in culture. 1174 4

We report a novel strategy for the preparation of neoglycoconjugates of oligosaccharides which are obtained after complete deacylation of bacterial deep rough lipopolysaccharides (LPS) isolated from recombinant Escherichia coli bacteria synthesizing a Kdo di-[alpha-Kdo-(2-->4)-alpha-Kdo-(2-->] and a Kdo trisaccharide [alpha-Kdo-(2-->8)-alpha-Kdo-(2-->4)-alpha-Kdo-(2-->] of Re-type and chlamydial LPS, respectively. Unlike acylated LPS, such oligosaccharides can be obtained in pure form and thus lead to well-defined neoglycoconjugates. Cleavage of the 1-phosphate of the lipid A moiety by alkaline phosphatase treatment leads to a free reducing glucosamine which can be further reacted with allylamine. After reductive amination, spacer elongation of the allyl group with cysteamine and activation with thiophosgene, the ligands were reacted with BSA. We have compared the immunological reactivity of such defined neoglycoconjugates obtained from natural sources with those obtained by chemical synthesis and report that such neoglycoconjugates are immunogenic and well suited as antigens for the study of epitope specificities of monoclonal antibodies. In addition, we have compared these conjugates with those in which ligands were coupled by glutardialdehyde to BSA. Our approach proved to be superior since the latter led upon immunization of mice to a relatively high percentage of antibodies that reacted with glutardialdehyde derivatized BSA without the carbohydrate ligand. This was not the case for cysteamine-spacered ligands coupled via their isothiocyanate-derivatives.
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PMID:A novel strategy for the synthesis of neoglycoconjugates from deacylated deep rough lipopolysaccharides. 1223 Sep 19

Amiodarone is an antiarrhythmic drug now more frequently used after a number of years in which the use had been on the decline due to a number of studies which reported side effects such as chronic toxicity, primarily in the lungs, liver and thyroid glands. Additionally, in some patients an increase in serum creatinine was noted, however the effect of amiodarone on renal function had never been closely examined. Thus, the aim of our study was to analyse the effects of amiodarone on renal function in rats. Experiments were carried out in male Wistar rats divided in two experimental groups: 1) a control group, (n=8), 2) a group that received a daily intraperitoneal injection of amiodarone (50 mg/kg body weight) for 6 days (n=5). At the end of the treatment, renal function was measured by clearance creatinine and acute clearance studies. Renal toxicity was evaluated by urinary N-acetyl-glucosamine and alkaline phosphatase. At the end of the experiment, histology studies were done. Rats treated with amiodarone had a higher serum creatinine (182%) and a lower glomerular filtration rate (53%), renal plasma flow (68%) and filtration fraction (62%) than controls. Rats treated with amiodarone also showed an increase in urinary N-acetyl-glucosamine (221%) and alkaline phosphatase (4.151%) excretion which corresponds with tubular alterations showed on electron microscopy. In conclusion our data confirm that amiodarone induces acute renal damage in the rat.
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PMID:Acute renal toxic effect of amiodarone in rats. 1271 May 96

It is generally believed that molecular mimicry between bacterial lipooligosaccharide (LOS) and nerve glycolipids may play an important pathogenic role in immune-mediated peripheral neuropathy. One of the putative infectious agents is Campylobacter jejuni (C. jejuni). To elucidate the structural basis for the molecular mimicry, we investigated the structure of the lipooligosaccharide (LOS) fraction of C. jejuni, strain HS19, and found that it includes at least two components, characterized as fast-and slow-moving bands (LF and LS) by thin-layer chromatography as revealed by cholera toxin B subunit (Ctxb) overlay. Structural analysis of the oligosaccharide portion of LS established that it had the following structure: Gal-GalNAc-(NeuAc)Gal-Hep-(Glc;PO(3)H)Hep-Kdo. The GM1-like epitope was validated by a terminal tetrasaccharide unit within this structure. On the other hand, analysis of LF revealed an entirely different structure: 1, 4'-bisphosphoryl glucosamine disaccharide N, N'-acylated by 3-(2-hydroxytetracosanoyloxy)octadecanoic acid at 2- and 2'-positions, which is consistent with that of lipid A. No GM1-like epitope was observed in LF. Both LS and LF interacted with Ctxb as demonstrated by TLC-overlay and sucrose density gradient centrifugation. Surprisingly, LF does not have the basic GM1 structure for interacting with Ctxb. Instead, the affinity of LF to Ctxb required that one or both of the phosphate groups be present in the glucosamine disaccharide residue because after alkaline phosphatase treatment the dephosphorylated LF was unable to bind to Ctxb. We conclude that LS is likely the component contributing to GM1-mimicry in autoimmune peripheral neuropathy and that the role of LF is not clear but may be associated with the initial activation of autoreactive T cells.
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PMID:Chemical validation of molecular mimicry: interaction of cholera toxin with Campylobacter lipooligosaccharides. 1722 1

We report for the first time that culture conditions, specifically culture medium supplementation with nucleotide-sugar precursors, can alter significantly the N-linked glycosylation of a recombinant protein in plant cell culture. Human secreted alkaline phosphatase produced in tobacco NT1 cell suspension cultures was used as a model system. Plant cell cultures were supplemented with ammonia (30 mM), galactose (1 mM) and glucosamine (10 mM) to improve the extent of N-linked glycosylation. The highest levels of cell density and active extracellular SEAP in supplemented cultures were on average 260 g/L and 0.21 U/mL, respectively, compared to 340 g/L and 0.4 U/mL in unsupplemented cultures. The glycosylation profile of SEAP produced in supplemented cultures was determined via electrospray ionization mass spectrometry with precursor ion scanning and compared to that of SEAP produced in unsupplemented cultures. In supplemented and unsupplemented cultures, two biantennary complex-type structures terminated with one or two N-acetylglucosamines and one paucimannosidic glycan structure comprised about 85% of the SEAP glycan pool. These three structures contained plant-specific xylose and fucose residues and their relative abundances were affected by each supplement. High mannose structures (6-9 mannose residues) accounted for the remaining 15% glycans in all cases. The highest proportion (approximately 66%) of a single complex-type biantennary glycan structure terminated in both antennae by N- acetylglucosamine was obtained with glucosamine supplementation versus only 6% in unsupplemented medium. This structure is amenable for in vitro modification to yield a more human-like glycan and could serve as a route to plant cell culture produced therapeutic glycoproteins.
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PMID:Influence of culture medium supplementation of tobacco NT1 cell suspension cultures on the N-glycosylation of human secreted alkaline phosphatase. 1723 9

Early in the pathological process of osteoarthritis (OA), subchondral bone remodelling, which is related to altered osteoblast metabolism, takes place. In the present study, we explored in human OA subchondral bone whether chondroitin sulfate (CS), glucosamine sulfate (GS), or both together affect the major bone biomarkers, osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL), and the pro-resorptive activity of OA osteoblasts. The effect of CS (200 mug/mL), GS (50 and 200 mug/mL), or both together on human OA subchondral bone osteoblasts, in the presence or absence of 1,25(OH)2D3 (vitamin D3) (50 nM), was determined on the bone biomarkers alkaline phosphatase and osteocalcin, on the expression (mRNA) and production (enzyme-linked immunosorbent assay) of bone remodelling factors OPG and RANKL, and on the pro-resorptive activity of these cells. For the latter experiments, human OA osteoblasts were incubated with differentiated peripheral blood mononuclear cells on a sub-micron synthetic calcium phosphate thin film. Data showed that CS and GS affected neither basal nor vitamin D3-induced alkaline phosphatase or osteocalcin release. Interestingly, OPG expression and production under basal conditions or vitamin D3 treatment were upregulated by CS and by both CS and GS incubated together. Under basal conditions, RANKL expression was significantly reduced by CS and by both drugs incubated together. Under vitamin D3, these drugs also showed a decrease in RANKL level, which, however, did not reach statistical significance. Importantly, under basal conditions, CS and both compounds combined significantly upregulated the expression ratio of OPG/RANKL. Vitamin D3 decreased this ratio, and GS further decreased it. Both drugs reduced the resorption activity, and statistical significance was reached for GS and when CS and GS were incubated together. Our data indicate that CS and GS do not overly affect cell integrity or bone biomarkers. Yet CS and both compounds together increase the expression ratio of OPG/RANKL, suggesting a positive effect on OA subchondral bone structural changes. This was confirmed by the decreased resorptive activity for the combination of CS and GS. These data are of major significance and may help to explain how these two drugs exert a positive effect on OA pathophysiology.
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PMID:Chondroitin and glucosamine sulfate in combination decrease the pro-resorptive properties of human osteoarthritis subchondral bone osteoblasts: a basic science study. 1799 99


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