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)

Transient hyperglycemia in patients receiving total parenteral nutrition may be associated with impaired immune function. The effects of short-term hyperglycemia on one aspect of antimicrobial immune function, ie, the ability of IgG to fix complement, were investigated. Aliquots of anti-human albumin, anti-horse ferritin, and anti-alkaline phosphatase were incubated for 0, 8, 16, 24, 48, and 96 hr with either 0 or 240 mg of glucose per deciliter of buffer. All samples were analyzed for the degree of glycation using a thiobarbituric acid assay, and for complement fixation ability using a microcomplement fixation assay. Significant increases in glycation over control samples were observed after only 16 hr (31 vs 15 mmol 5-hydroxymethylfurfural/mol IgG, p less than 0.01). Complement fixation was significantly altered after 48 hr of incubation (76 +/- 5% vs 90 +/- 8% total serum complement fixed by albumin/anti-albumin complex, p less than 0.03) when four of the 84 (4.7%) IgG lysine residues were glycated. It is demonstrated that a significant reduction in complement fixation by immunoglobulin occurs with elevated glucose concentrations and that this may play a clinically significant role in transiently hyperglycemic patients.
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PMID:Nonenzymatic glycosylation of immunoglobulin G impairs complement fixation. 200 35

Steric and chemical evidence had previously shown that residues Lys-7 and/or Arg-10 of bovine pancreatic RNAase A could belong to the p2 phosphate-binding subsite, adjacent to the 3' side of the main site p1. In the present work chemical modification of the enzyme with pyridoxal 5'-phosphate and cyclohexane-1,2-dione was carried out in order to identify these residues positively as part of the p2 site. The reaction with pyridoxal 5'-phosphate yields three monosubstituted derivatives, at Lys-1, Lys-7 and Lys-41. A strong decrease in the yield of derivatives at Lys-7 and Lys-41 was observed when either p1 or p2 was specifically blocked by 5'-AMP or 3'-AMP respectively. These experiments indicate that both sites are needed for the reaction of pyridoxal 5'-phosphate with RNAase A to take place. The positive charge in one of the sites interacts with the phosphate group of pyridoxal 5'-phosphate, giving the proper orientation to the carbonyl group, which then reacts with the lysine residue present in the other site. The absence of reaction between pyridoxal 5'-phosphate and an RNAase derivative that has the p2 site blocked supports this hypothesis. Labelling of Lys-7 with pyridoxal 5'-phosphate has a more pronounced effect on the kinetics with RNA than with the smaller substrate 2',3'-cyclic CMP. In addition, when the phosphate moiety of the 5'-phosphopyridoxyl group was removed with alkaline phosphatase the kinetic constants with 2',3'-cyclic CMP returned to values very similar to those of the native enzyme, whereas a higher Km and lower Vmax. were still observed for RNA. This indicates that this new derivative has recovered a free p1 site and, hence, the capability to act on 2',3'-cyclic CMP, but the presence of the pyridoxyl group bound to Lys-7 is still blocking a secondary phosphate-binding site, namely p2. Finally, reaction of cyclohexane-1,2-dione at Arg-10 is suppressed in the presence of 3'-AMP but only a 19% decrease is observed with 5'-AMP, suggesting that Arg-10 is also close to the p2 phosphate-binding subsite.
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PMID:Chemical modification by pyridoxal 5'-phosphate and cyclohexane-1,2-dione indicates that Lys-7 and Arg-10 are involved in the p2 phosphate-binding subsite of bovine pancreatic ribonuclease A. 211 Nov 31

Plasma carnitine levels were determined in 17 patients maintained on long-term total parenteral nutrition (TPN) for a mean (+/- SEM) period of 69 +/- 11 months (range 12-196). All had severe malabsorption and were dependent on intravenous feeding. Plasma carnitine was determined by a modified Cederblad enzymatic method. Mean plasma carnitine was significantly below the mean normal for females (p less than 0.02) and borderline low for males (p = 0.07). In six patients the levels were below the low normal range, and in five others they were at the lowest levels of normal. Of the six patients with normal levels, three had elevated serum creatinine, indicating renal dysfunction which may by itself elevate plasma carnitine. In 10 patients the plasma levels of lysine (a carnitine precursor) were determined and found to be lower than normal (p less than 0.05). Plasma carnitine levels correlated positively with serum albumin (r = 0.62, p less than 0.05), and negatively with serum alkaline phosphatase (r = -0.64, p less than 0.05). Thus, patients maintained on long-term TPN may have low plasma carnitine, which could represent carnitine deficiency. The low plasma carnitine may be related to a deficiency of the carnitine precursor lysine. Further studies are required to determine the significance of the low plasma carnitine and whether carnitine supplementation should be required in long-term TPN.
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PMID:Low plasma carnitine in patients on prolonged total parenteral nutrition: association with low plasma lysine. 211 37

Many proteins are now known to be anchored to the plasma membrane by a phosphatidylinositol-glycan (PI-G) moiety that is attached to their COOH termini. Placental alkaline phosphatase (PLAP) has been used as a model for investigating mechanisms involved in the COOH-terminal processing of PI-G-tailed proteins. The COOH-terminal domain of pre-pro-PLAP provides a signal for processing during which a largely hydrophobic 29-residue COOH-terminal peptide is removed, and the PI-G moiety is added to the newly exposed Asp-484 terminus. This cleavage/attachment site was subjected to an almost saturation mutagenesis, and the enzymatic activities, COOH-terminal processing, and cellular localizations of the various mutant PLAP forms were determined. Substitution of Asp-484 by glycine, alanine, cysteine, asparagine, or serine (category I) resulted in PI-G-tailed and enzymatically active proteins. However, not all category I mutant proteins were PI-G tailed to the same extent. Pre-pro-PLAP with other substituents at position 484 (threonine, proline, methionine, valine, leucine, tyrosine, tryptophan, lysine, glutamic acid, and glutamine; category II) were expressed, as well as the category I amino acids, but there was little or no processing to the PI-G-tailed form, and this latter group exhibited very low enzyme activity. The bulk of the PLAP protein produced by category II mutants and some produced by category I mutants were sequestered within the cell, apparently in the endoplasmic reticulum (ER). Most likely, certain amino acids at residue 484 are preferred because they yield better substrates for the putative "transamidating" enzyme. In transfected COS cells, at least, posttranslational PI-G-tail processing does not go to completion even for preferred substrates. Apparently PI-G tailing is a requisite for transport from the ER and for PLAP enzyme activity. Proteins that are not transamidated are apparently retained in the ER in an inactive conformation.
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PMID:Selectivity of the cleavage/attachment site of phosphatidylinositol-glycan-anchored membrane proteins determined by site-specific mutagenesis at Asp-484 of placental alkaline phosphatase. 215 84

Mouse L929 cells were used to study the mechanism of cAMP induction of alkaline phosphatase (AP) activity. Following treatment with 200 microM 8-chlorophenylthio-cAMP (CPT-cAMP), alkaline phosphatase enzyme activity was observed to increase 80-fold after 24 h. The CPT-cAMP dose response of the alkaline phosphatase enzyme activity correlated well with the CPT-cAMP activation of cAMP-dependent protein kinase in L cells. A cDNA clone for the alkaline phosphatase was isolated and used to demonstrate a 10-fold increase in alkaline phosphatase mRNA levels after a 24-h treatment of L cells with CPT-cAMP. Increased mRNA levels were first detected 4-6 h, after CPT-cAMP treatment, and the level of alkaline phosphatase mRNA decreased rapidly after removal of CPT-cAMP. In vitro nuclear transcription studies showed that a 3-fold increase in alkaline phosphatase gene transcription was detectable 6 h after CPT treatment, and this increase was blocked by cycloheximide. In order to determine if the catalytic (C) subunit of cAMP-dependent protein kinase was able to mediate the induction of AP, L cells were transfected with expression vectors containing the metallothionein promoter and coding for the C alpha isoform of the catalytic subunit of cAMP-dependent protein kinase or for a catalytic subunit in which lysine 72 had been mutated to methionine (C alpha K72M). Zinc treatment of stably transfected cells expressing the wild-type C subunit showed an increase in protein kinase activity and an increase in AP activity. Zinc treatment of cells containing the mutant C subunit expression vector produced an increase in the amount of a protein which was recognized by C subunit antibodies on Western blots, but these cells showed no increase in protein kinase activity or in AP activity. We conclude that the C subunit is sufficient for transcriptional induction of the AP gene and that the phosphotransferase activity of the C subunit is required for this induction.
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PMID:Induction of alkaline phosphatase in mouse L cells by overexpression of the catalytic subunit of cAMP-dependent protein kinase. 216 96

The first step in the intestinal absorption of phosphorylated forms of vitamin B6 is intraluminal hydrolysis mediated by alkaline phosphatase. The present studies were performed to evaluate the effect of amino acids and oligopeptides, the products of protein digestion, on the hydrolysis of pyridoxal 5'-phosphate. Models utilized rats and included a cell-free in vitro system and the in vivo, single-pass, perfused jejunal segment. In vitro all amino acids and oligopeptides tested significantly inhibited pyridoxal 5'-phosphate decay (hydrolysis). The degree of inhibition of decay was dependent on the particular compound used, the concentration of that compound, and the pH of the medium. Similar effects for L-lysine concentration and perfusate pH were demonstrated in perfused segments in vivo; by contrast, L-lysine had no effect on pyridoxine uptake. These studies demonstrate that intraluminal hydrolysis of phosphorylated vitamin B6 may be modulated by yet other intraluminal constituents and conditions.
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PMID:Intestinal hydrolysis of pyridoxal 5'-phosphate in vitro and in vivo in the rat. Effect of amino acids and oligopeptides. 229 87

The effect of lithium and other antipsychotic drugs on the renal function in patients with manic-depressive disorders has been investigated. Thirty-four patients (5 males and 29 females) treated with lithium and 21 patients (6 males and 15 females) on other antipsychotic drugs were studied. A control group of 10 persons consisting of healthy subjects, all of whom were taking no medication was also studied. No significant differences in the treatment duration were present between the patients investigated. Although few patients on lithium had glomerular filtration reduced, no statistically significant difference in creatinine clearance was found between the groups. None of the patients had a disturbance in the reabsorption of glucose, amino acids (histidine, lysine, valine, glutamine, glycine, serine, taurine, threonine, alanine, isoleucine) and beta 2-microglobulin. Patients treated with lithium had a significantly reduced urine concentration and higher daily diuresis than did the other two studied groups. A significantly higher overnight elimination of alkaline phosphatase was found in a group of patients taking other antipsychotic drugs. The attained results suggest tubular lesions in patients with manic-depressive psychosis occurring in the association with the prophylactic use of lithium and, at same time, the possibility of the other in association with the other antipsychotic drugs.
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PMID:[Effect of long-term use of lithium on kidney function]. 236 20

In this study a double immunohistochemical staining procedure is described for the simultaneous demonstration of antigen expressing cells and replicating cells in rat thymus. As markers for cell surface antigen expression a monoclonal antibody against Ia-expressing cells (His 19) and a monoclonal antibody against cells of the monocyte-macrophage lineage (ED2) were used. Replicating cells were demonstrated by the incorporation of 5-bromodeoxyuridine (BrdUrd). Tissue pieces were fixed in a periodate-lysine-paraformaldehyde fixative and embedded in glycol methacrylate. To demonstrate Ia-expressing cells or ED2-positive macrophages in plastic embedded sections a digestion with trypsin is necessary. The staining procedure was applied sequentially and was performed with a peroxidase and an alkaline phosphatase labeled reagent yielding respectively a brown and a blue reaction product. Results with this staining procedure on plastic embedded sections of rat thymus, an organ with a high DNA synthesizing capacity, showed incorporation of BrdUrd predominantly in the cortex. ED2-positive macrophages were only found in the cortex. The Ia-positive epithelial reticular cells demonstrated extremely well their stellate form.
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PMID:Simultaneous immunohistochemical demonstration of antigen expression and 5-bromodeoxyuridine incorporation in plastic embedded sections. 243 84

We have expressed the 174-263 fragment (kringle-2 domain) of human tissue-type plasminogen activator (t-PA) in Escherichia coli by secretion into the periplasmic space using the alkaline phosphatase promoter and stII enterotoxin signal sequence. A large portion of the secreted protein is associated with an insoluble cellular fraction. This material can be solubilized by extraction with denaturant and reducing agent and then recovered in active form by refolding in the presence of reduced and oxidized glutathione. Kringle-2 is then easily purified by affinity chromatography on lysine-Sepharose followed by cation-exchange chromatography. The isolated protein has an amino acid composition and N-terminal sequence as expected for the 174-263 fragment of t-PA, indicating that the signal peptide has been properly removed. Circular dichroic spectra suggest that the protein is folded similar to the kringle-4 domain of plasminogen [Castellino et al. (1986) Arch. Biochem. Biophys. 247, 312-320]. Equilibrium dialysis experiments indicate a single binding site on kringle-2 for L-lysine having a KD of 100 microM. Using a method based on elution of kringle from lysine-Separose with omega-aminocarboxylic acids [Winn et al. (1980) Eur. J. Biochem. 104, 579-586], we have shown the lysine binding site of t-PA kringle-2 to have a preference for a ligand with 8.8-A separation between amine and carboxylate functions. Charge interactions with the epsilon-amino group of L-lysine are important in binding since the affinities for N epsilon-acetyl-L-lysine, L-arginine, and gamma-guanidinobutyric acid are decreased greater than 2000-fold, 200-fold, and 12-fold, respectively, relative to the affinity for L-lysine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and characterization of tissue plasminogen activator kringle-2 domain expressed in Escherichia coli. 249 71

1. The carbohydrate content of isozyme K of alkaline phosphatase (EC 3.1.3.1) from harp seal intestinal mucosa was examined. The presence of N-acetylglucosamine, N-acetylgalactosamine and considerable amounts of mannose residues was shown. 2. The amino acid content of seal alkaline phosphatase was determined. A high extent of homology (85%) between bovine and seal alkaline phosphatases was demonstrated. 3. By chemical modification lysine, dicarboxylic acids, arginine and tyrosine residues of tetrameric seal alkaline phosphatase are located near or at the active site. By contrast, the modification of either thiol or imidazole groups resulted in no alterations of the enzyme activity. 4. It has been demonstrated that inorganic phosphate is an inhibitor of alkaline phosphatase and entirely prevents the enzyme inactivation with succinic anhydride.
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PMID:Chemical modification and composition of tetrameric isozyme K of alkaline phosphatase from harp seal intestinal mucosa. 270 30


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