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)

A close correlation between the intensity of tissue reaction in skeletal muscles and the localization of some enzymes in the bladder of C. bovis was demonstrated by histochemical methods. The most intensive tissue reaction was observed around the portion of bladder surrounding the opening of spiral canal, the tegument and subtegumental cells of which exhibit a high activity of alkaline phosphatase and acid phosphatase. Around this portion of bladder the tissue reaction is very strong, whereas around the remaining portion of the bladder, without any activity of these enzymes, the reaction is weak. The basic type of the reaction around the portion with alkaline and acid phosphatase activity is the formation of a pseudoepithelial rim, in which occur secondary changes leading to histochemical changes inside and around this rim. The cells of the unchanged pseudoepithelial rim contain proteins with tyrosine, tryptophan and cysteine. Among the cells is a large number of reticular fibres. Flat foci localized directly in this rim contain mostly fibrilar structures rich in acid mucosubstances with carboxyl and sulphate groups which are labile to testicular hyaluronidase and neuraminidase. They contain also a small amount of neutral mucosubstances and give negative reactions for tyrosine, tryptophan and cysteine. Fibrilar structure in these foci undergo dystrophic calcification. A conspicuous accumulation of mast cells is visible in the layers under the pseudoepithelial rim and clusters of cells containing lipopigment are present at the periphery of the connective tissue layer.
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PMID:Histochemistry of tissue reaction in skeletal muscles of cattle experimentally infected with Cysticercus bovis. 74 48

Nerve growth factor (NGF) is essential for the development and differentiation of sympathetic and sensory neurons. Recently, NGF receptors were demonstrated in non-neural cells, and several mesenchymal cell types including lymphocytes and skeletal myotubes were shown to be stimulated to proliferate by NGF. Our purpose was to examine for the presence of functional NGF receptors in osteoblasts. Bone cells from chick calvaria were used as a model; PC-12 cells derived from rat adrenal pheochromocytoma were used as positive controls. NGF was examined for functions in chick bone cells by studying effects on (1) [3H]-thymidine incorporation; (2) alkaline phosphatase (ALP) activity; and (3) protein tyrosine phosphorylation. Effects of NGF on thymidine incorporation and protein tyrosine phosphorylation by PC-12 cells were also measured. A radioreceptor assay was used to test for the presence of receptors. In chick calvarial cells, NGF had no effect on thymidine incorporation, ALP activity or protein tyrosine phosphorylation. Radioreceptor assay with bone cells showed no evidence of NGF receptors. In contrast, in PC-12 cells, NGF (1) decreased thymidine incorporation; (2) increased protein tyrosine phosphorylation; and (3) showed receptor activity by radioreceptor assay. In conclusion, unlike several other mesenchymal cell types, chick bone cells show no evidence of NGF receptors or functional responses to NGF in vitro.
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PMID:Evidence for a lack of functional receptors for nerve growth factor (NGF) in chick bone cells in vitro. 144 57

Lipopeptides are potential vaccine candidates with a built-in adjuvant property. To circumvent the present chemical route of synthesis for lipopeptide-antigen conjugates, the lipoprotein property of the pColE2-P9-encoded lysis protein, CelB, was used to create the bacterial fusion plasmid, pKLY3, to produce lipopeptide-antigen chimeras in Escherichia coli. Plasmid pKLY3 is a derivative of pKK233-2 with the origin of replication of the single-stranded DNA phage, fl. Under control of the promoter, ptrc, is the 5' end of the celB gene coding for a lipoprotein signal peptide and the first five amino acids (aa) (CQANY) of the mature lysis protein. As model systems for the synthesis of small and large lipopeptide-antigens, DNA sequences coding for the P2 peptide and E. coli alkaline phosphatase (PhoA) were fused in frame to the region of celB coding for a lipoprotein signal peptide and CQANY. P2 is a 12-aa peptide including a tyrosine phosphorylation site of the epidermal growth factor receptor (EGF-R). Inducible expression of stable lipohexapeptide CQANYV, lipo-CQANY-P2, and lipo-CQANYA-PhoA, was demonstrated. Similar expression was obtained for lipo-CIEGR-P2 and lipo-CIEGRA-PhoA in which IEGR is a cleavage recognition site for the blood coagulation factor, Xa. Like QANY, IEGR is predicted to form a beta-turn structure. The presence of a lipid moiety on the products was confirmed by demonstrating the incorporation of radioactive palmitic acid and inhibition of processing by globomycin. The lipid-modified peptides were also identified by incorporation of radioactive tyrosine, and the nature of the P2 peptide was verified immunologically.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A fusion plasmid for the synthesis of lipopeptide-antigen chimeras in Escherichia coli. 162 39

In this report we describe the purification of the murine interleukin 3 receptor (mIL-3R) to apparent homogeneity using a two-step procedure involving biotinylated mIL-3 (B-mIL-3) and affinity binding to immobilized antiphosphotyrosine and streptavidin agarose (SA). Purification was monitored using an assay for detergent solubilized-mIL-3Rs that utilized unglycosylated 125I-mIL-3 and concanavalin A (ConA)-Sepharose beads. The final material consisted of a 140-kDa tyrosine and serine phosphorylated protein that was greater than 98% pure as assessed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of either [35S]methionine-labeled, silver-stained, or radioiodinated preparations. Characterization of the purified receptor revealed that it migrated identically under reducing and nonreducing conditions in SDS gels, possessed 10 kDa of N-linked carbohydrate, and was cleaved upon storage at 4 degrees C to a 70-kDa form. These properties suggested that the purified mIL-3R was identical to that identified by cross-linking studies. The KD of the purified receptor was 1-5 nM, similar to estimates obtained using intact normal mouse bone marrow cells and mIL-3-dependent cell lines. The two-step purification procedure also isolated a 120-kDa serine phosphorylated but nontyrosine phosphorylated mIL-3R species. Apart from phosphorylation differences, the 140- and 120-kDa species were apparently identical, yielding, after alkaline phosphatase treatment, the same molecular mass on SDS gels and similar chymotryptic peptide maps. Amino acid sequences and composition data obtained from the more abundant and more stable serine phosphorylated 120-kDa mIL-3R, further purified by SDS-polyacrylamide gel electrophoresis, suggested that the purified mIL-3R may be identical to the predicted sequence of the recently isolated cDNA clone AIC2A. This was further suggested by comparing chymotryptic maps of the 120-kDa mIL-3R with the Aic2A protein and using antibodies corresponding to the amino and carboxyl termini of the AIC2A cDNA product. However, the Aic2A protein, when expressed on the surface of COS or 3T3 cells or following detergent solubilization and partial purification with biotinylated mIL-3 and SA, displayed a substantially lower affinity for mIL-3.
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PMID:Purification of the murine interleukin 3 receptor. 164 33

Treatment of bovine chromaffin cells with insulin-like growth factor-I (IGF-I) caused the activation of a protein kinase that phosphorylates microtubule-associated protein-2 (MAP-2) in vitro. Activation of MAP-2 kinase by IGF-I varied with the time of treatment (maximal at 10-15 min) and the concentration of IGF-I (maximal at 10 nM). The IGF-I-activated MAP-2 kinase was localized to the soluble fraction of chromaffin cell extracts and required Mg2+ for activity. The IGF-I-activated kinase also phosphorylated myelin basic protein, but had little or no activity toward histones or ribosomal S6 protein. To examine the role of protein tyrosine phosphorylation in the activation of the MAP-2 kinase, we isolated phosphotyrosine (PTyr)-containing proteins from chromaffin cells by immunoaffinity adsorption on anti-PTyr-Sepharose beads. Anti-PTyr-Sepharose eluates from IGF-I-treated cells showed increased MAP-2 kinase activity; thus, the MAP-2 kinase (or a closely associated protein) appears to be a PTyr-containing protein. Treatment of anti-PTyr-Sepharose eluates or crude chromaffin cell extracts with alkaline phosphatase significantly decreased kinase activity toward myelin basic protein, indicating that phosphorylation of the IGF-I-activated kinase is required for its activity.
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PMID:Activation of a microtubule-associated protein-2 kinase by insulin-like growth factor-I in bovine chromaffin cells. 165 24

We investigated whether phosphorylation of the essential components involved in the 3' end processing of mRNAs was required for mRNA polyadenylation. The proteins in HeLa nuclear extract were dephosphorylated with alkaline phosphatase, which is known to remove the phosphate moieties from serine and tyrosine. The dephosphorylated extract was used for analyzing cleavage-dependent polyadenylation of SV40 late pre-mRNA. The phosphatase treatment of the extract completely blocked the polyadenylation reaction, whereas dephosphorylation of the extract did not inhibit the cleavage reaction. Since the cleavage depends upon functional integrity of the specificity factor, it is unlikely that the phosphorylated state of the latter factor is required for the 3' end processing. Sodium vanadate, a potent inhibitor of alkaline phosphatase, markedly reduced the inhibitory effect of the phosphatase on the polyadenylation reaction. Dephosphorylation of the extract also prevented formation of the polyadenylation-specific complex with pre-mRNA, whereas the cleavage-specific complexes were formed under this condition. The Mn-dependent polyadenylation, which is largely poly(A) extension reaction, was relatively resistant to the phosphatase treatment. These data indicate that phosphorylation of a key factor is essential for the 3' end processing of pre-mRNA, and suggest that the factor may be poly(A) polymerase.
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PMID:Polyadenylation of SV40 late pre-mRNA is dependent on phosphorylation of an essential component associated with the 3' end processing machinery. 166 46

Nascent precursors of phosphatidylinositol-glycan (PI-G)-linked membrane proteins contain a hydrophobic COOH-terminal sequence of 15-30 residues that is eliminated during processing to yield a newly exposed COOH terminus to which the PI-G moiety is added. There is no consensus as to the primary structure of the terminal peptide but there is a specific requirement for the amino acid destined to become the COOH terminus. In nascent human placental alkaline phosphatase (PLAP), the PI-G tail is attached to Asp-484. Site-directed mutants with glycine, alanine, cysteine, serine, or asparagine (category I) at residue 484 become PI-G tailed, appear in the plasma membrane, and are enzymatically active when expressed in COS cells. Although mutants with glutamic acid, glutamine, proline, tryptophan, leucine, valine, phenylalanine, threonine, methionine, and tyrosine (category II) are expressed equally well, only small amounts appear on the plasma membrane. Furthermore, they are not PI-G tailed and have little alkaline phosphatase activity. Studies with truncated PLAP-489 rule out nonspecific conformational changes in category II mutant proteins as a reason for their failure to be processed in COS cells and point to a specific COOH-terminal processing enzyme. Direct evidence that the selectivity for category I amino acids is enzymatically determined was obtained in a cell-free translation/processing system by using rabbit reticulocyte lysate and CHO cell rough microsomal membranes. In this in vitro system, both category I and category II mutants of PLAP-513 were translated, glycosylated, and cleaved by NH2-terminal signal peptidase. However, an additional and selective cleavage at residue 484 was observed only with category I mutants.
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PMID:Selectivity at the cleavage/attachment site of phosphatidylinositol-glycan anchored membrane proteins is enzymatically determined. 170 Apr 20

A variety of signal transduction pathways contribute to the regulation of transcription in mammalian cells. Several of these pathways ultimately rely upon the interaction of transcription factors with genetic sequences termed response elements in the promoter regions of some genes. The biochemical mechanisms that control the levels and state of activation of transcription factors are poorly understood. However, specific phosphorylation events mediated by protein kinase C, growth factor receptor-linked tyrosine kinases, and protein kinase A clearly participate in the regulation of these signal transduction pathways. To understand the relationship between activation and/or inhibition of these pathways and regulation of gene expression controlled by specific response elements, cell lines were prepared containing the TPA response element (TRE), serum response element (SRE), or cyclic AMP response element (CRE) fused to a gene encoding a secretable form of alkaline phosphatase (SEAP). These TRE-SEAP, SRE-SEAP, and CRE-SEAP cells exhibit dramatic increases in alkaline phosphatase (AP) activity following exposure to TPA, PDGF, or forskolin. Down regulation of protein kinase C or inhibition of tyrosine kinase activity blocked the stimulation of AP activity caused by TPA or PDGF. These cell lines can be used to characterize existing inhibitors, and to identify new agents that affect specific signal transduction pathways in mammalian cells.
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PMID:Mammalian cell lines engineered to identify inhibitors of specific signal transduction pathways. 171 Nov 89

1. The presence of high-Mr and low-Mr acid phosphatases [orthophosphoric-monoester phosphohydrolase, (acid optimum), EC 3.1.3.2] in the skeletal muscle of frog Rana esculenta was reported. 2. The subcellular localization and some characteristics of both enzymes were also described. 3. The low-Mr AcPase was purified to homogeneity. The enzyme did not absorb on Concanavalin A-Sepharose 4B indicating that this was not a glycoprotein. 4. The enzyme is homogeneous on polyacrylamide gel electrophoresis and moves as a single band of Mr 13.7 +/- 0.8 kDa in the presence of sodium dodecyl sulphate. 5. The Mr of the native enzyme was 14.0 +/- 1.1 kDa as determined by gel filtration on a Sephadex G-100 column. The isoelectric point was 6.02. 6. The enzyme was strongly inhibited by 1 mM Ag+, Hg2+, Sn2+ and Cu2+ while other cations both at 10(-2) and 10(-3) M showed little or no effect. 7. The enzyme was insensitive to NaF and tartrate but was strongly deactivated by formaldehyde, PMB, Iodoacetamide and Triton X-100. Phosphate was a competitive inhibitor (k1 = 0.83 mM). 8. The best substrate for the enzyme was p-nitrophenylphosphate but phenylphosphate, flavin mononucleotide and o-P-tyrosine were also hydrolyzed, though at different rates. 9. The enzyme activity was enhanced in the presence of methanol, ethanol, acetone and glycerol indicating a phosphotransferase activity.
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PMID:Acid phosphatases in the frog (Rana esculenta) skeletal muscle. Purification and some properties of the low molecular weight enzyme. 178 53

The insulin resistance seen in diabetes mellitus has been attributed partly to impaired autophosphorylation of the insulin receptor. It has been suggested that the phosphorylation of serine and/or threonine residues of the insulin receptor may reduce tyrosine autophosphorylation in streptozotocin-induced diabetic rats (STZ-D rats). To elucidate the mechanisms of decreased autophosphorylation of the insulin receptor in diabetic rats, we have investigated the effect of dephosphorylation of the insulin receptor by alkaline phosphatase on the insulin- and protein kinase-stimulating incorporation of 32P into the receptor of the liver from STZ-D rats. Both basal and insulin-stimulated autophosphorylations of the insulin receptor from STZ-D rats were significantly impaired to those from normal rats. Dephosphorylation of the insulin receptor by alkaline phosphatase resulted in an increase in insulin-stimulated autophosphorylation of the insulin receptor from STZ-D rats (43 +/- 13% to 66 +/- 14%, P less than 0.05), but not from normal rats (100% to 109 +/- 12%, NS). Although maximal autophosphorylation of the dephosphorylated insulin receptor was still lower in STZ-D rats than in normal rats, the increase in insulin-stimulated autophosphorylation of the insulin receptor from STZ-D rats by dephosphorylation was higher than that from normal (159.2 +/- 27.2% vs 108.0 +/- 12.4%, p less than 0.01), supporting the idea that the residues of the insulin receptor of STZ-D rats was highly phosphorylated.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dephosphorylation of the insulin receptor partially restores the decreased autophosphorylation in streptozotocin induced diabetic rats. 181 77


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