Correlation of acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain

• 1.1. Neonatal mice received subcutaneous injections of buffer, thiourea (TU) or propylthiouracil (PTU).
• 2.2. The PTU-treated mice were sacrificed on postnatal day 14 (P14) and the TU-treated mice on P28.
• 3.3. Brain weights of the TU- and PTU-treated mice were not significantly different from the controls.
• 4.4. Acid but not alkaline phosphatase activity in the braistem decreased after TU and PTU treatment.
• 5.5. Myelination as indicated by intensity of luxol fast blue staining was weaker in drug-treated animals.
• 6.6. The level of myelin marker enzyme, 2′,3′-cyclic nucleotide 3′-phosphohydrolase, was lower in the brainstem of PTU-treated animals.
• 7.7. The results suggest a correlation between acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain.

     

Prostaglandin E2/parathyroid hormone-induced suppression of alkaline phosphatase activity is mediated by protein kinase C

• 1.1. Bone resorptive factors, prostaglandin E2 and parathyroid hormone are shown to suppress alkaline phosphatase activity in a rat osteoblastic cell line.
• 2.2. Phorbol myristate acetate, but not dibutyryl cAMP or calcium ionophore can suppress alkaline phosphatase activity.
• 3.3. The protein kinase C inhibitors (H89, staurosporine) are able to block the suppression of alkaline phosphatase activity induced by prostaglandin E2 and parathyroid hormone.
• 4.4. These data suggest that protein kinase C is involved in the inhibition of alkaline phosphatase activity induced by prostaglandin E2 and parathyroid hormone.

     

Essential tyrosyl residues of human placental alkaline phosphatase

• 1.1. Human placental alkaline phosphatase was inactivated with tetranitromethane in a biphasic process.
• 2.2. Spectral and amino acid analysis demonstrated that the inactivation was due to the conversion of tyrosine residues to 3-nitrotyrosine.
• 3.3. The inactivation process showed saturation kinetics.
• 4.4. Protection of the enzyme against tetranitromethane inactivation was afforded by inorganic phosphate.
• 5.5. The binding affinity between the modified enzyme and inorganic phosphate was decreased.
• 6.6. Our results suggest the involvement of tyrosyl residues in the locus of phosphoryl site of the phosphorylated enzyme forms.

     

The haemocytes and the activities of leucine aminopeptidase and alkaline phosphatase during development of Ceratitis capitata: Specific secretion of a leucine aminopeptidase isozyme

• 1.1. The types of haemocytes during larval development were studied.
• 2.2. The developmental profile of leucine aminopeptidase and alkaline phosphatase was studied. The maximum LAP activity was found to be in early larval development, while the maximum alkaline phosphatase during the white pupal stage.
• 3.3. These activities were compared with those determined in cell-free haemolymph.
• 4.4. Both hydrolytic enzymes have been found histochemically in the prohaemocytes and in the plasmatocytes.
• 5.5. In cultured haemocytes experiments it was found that 64% of the total LAP activity was secreted into the incubation medium, while electrophoretic analysis of released LAP activity demonstrated that only LAP A isozyme was secreted.
• 6.6. Based on the above results we suggest that both hydrolytic enzymes are functionally important throughout larval development.

     

He partial sequencing of human nonspecific (bone/liver/kidney) alkaline phosphatase gene

• 1.1. A charon 4A human fetal liver genomic library was screened for human nonspecific alkaline phosphatase gene using the cloned human bone cDNA as a hybridization probe.
• 2.2. A clone 2.2 Kb DNA was sequenced and found to contain a piece of sequences encoding the 4–44th amino acids of NH; terminus.
• 3.3. The other cloned 1.6Kb DNA contains two segments of sequences each corresponding to two separate regions of the cDNA for alkaline phosphatase. The first segment of the DNA codes for the 83–141st amino acids whereas the second for 141–199th.

     

Effects of short chain fatty acid,sodium butyrate,on osteoblastic cells and osteoclastic cells

• 1.1. Sodium butyrate increased alkaline phosphatase (ALP) activity of cloned osteoblastic cell line MC3T3-El by the stimulation of de novo enzyme synthesis.
• 2.2. Sodium butyrate did not affect mature osteoblastic cells but affected preosteoblastic cells.
• 3.3. Sodium butyrate decreased tartrate resistant acid phosphatase (TRACP)-positive multinucleated cells (MNC) formation from bone marrow cells. This related to the cytotoxicity of sodium butyrate on bone marrow cells.

     

Properties of an alkaline phosphatase from the dinoflagellate Peridinium cinctum

• 1.1. Alkaline phosphatase (EC 3.1.3.1) from the dinoflagellate Peridinium cinctum, the Lake Kinneret bloom alga, has been partially purified by gel filtration.
• 2.2. The enzyme could be easily extracted using a distilled water/chloroform mixture suggesting that the alkaline phosphatase of Peridinium is particularly labile.
• 3.3. The molecular weight of the enzyme was estimated as 158,000 ± 5000. The enzyme showed a broad pH optimum (in the range pH 8.0–8.5), had a K_m of 0.45 mM for p-nitrophenylphosphate as substrate and was stable to repeated freeze/thawing cycles.
• 4.4. The enzyme was strongly activated by Mg²⁺ whereas Zn²⁺ (and to a lesser extent Cd²⁺) was an effective inhibitor of the enzyme. Cu²⁺ activated the enzyme at low concentrations, although at higher concentrations inhibited the enzyme. This effect of metals on the Peridinium alkaline phosphatase could be environmentally important since underwater hot springs, containing high concentrations of copper, enter the lake.

     

Human seminal phosphatase: Properties and comparison with plant phosphatases

• 1.1. Phosphatase activities were determined in various seminal fluid and plant tissues.
• 2.2. Human semen showed a markedly higher phosphatase activity, and some plants and mushrooms exhibited a considerably higher phosphatase activity.
• 3.3. Phosphatase purified from human seminal fluid showed a pH optimum of 5–6 and was potently inhibited by l-(+)-tartrate.
• 4.4. Tartrate could not inhibit most plant phosphatases, but inhibited the mushroom phosphatase with a one-order lower affinity than that of the seminal enzyme.

     

The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters

• 1.1. The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa.
• 2.2. Lactase activity is unaffected by cortisol.
• 3.3. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males.
• 4.4. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.

     

Cellular and intracellular localization of catalase and acid phosphatase in the midgut of Lumbricus terrestris L.: A cell fractionation study

• 1.1. Cellular and intracellular localization of catalase and acid phosphomonoesterase in the midgut of Lumbricus terrestris was studied by use of tissue fractionation.
• 2.2. At least 60–70% of the catalase resides in the chloragocyte cytosol and the remaining 30–40% resides in gut epithelium peroxisomes.
• 3.3. One of the main functions of the chloragocyte catalase is probably scavenging for H₂O₂ arising from the interaction between blood heme-protein and oxygen.
• 4.4. A simple method for the histochemical detection of cytosol catalase is proposed.
• 5.5. About 10% of the gut acid phosphatase resides in chloragocyte lysosomes. The chloragosomes contain no acid phosphatase.

     

Purification and some properties of an atypical alkaline p-nitrophenylphosphate phosphatase activity from Halobacterium halobium

• 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
• 2.2. The enzyme has an apparent molecular weight of 24,000.
• 3.3. A K_m value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
• 4.4. The enzyme is selectively activated and stabilized by Mn²⁺.
• 5.5. It requires high salt concentrations for stability and maximum activity.
• 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.

     

Correlation of water translocation,cuticle dehydration and post-ecdysial sclerotization by the american cockroach

• 1.1. Haemolymph volume decreases during the initial 16 hr post-ecdysial period, increases after water ingestion and subsequently drops until the inter-ecdysial level is reached.
• 2.2. Total body water follows a similar pattern, but the changes are not as pronounced.
• 3.3. Tissue water is inversely proportional to the total body water.
• 4.4. Soluble cuticle protein declines throughout the initial 16 hr period while both β-glucosidase and alkaline phosphatase activity is lost within 6 hr after ecdysis.
• 5.5. Dehydration of the cuticle also occurs during the immediate 6 hr post-ecdysial period.
• 6.6. These data suggest that the formation of the protein-insoluble matrix is linked with water loss.
• 7.7. Water removal may decrease the distance between molecules allowing specific reactions to take place.

     

Serum chemistry profiles for Lechwe waterbucks (Kobus leche): Variations with age and sex

• 1.1. Over an 8-year period, 19 biochemical parameters have been determined at various ages in the blood serum of 92 clinically healthy Lechwe waterbucks (Kobus leche), 33 males and 59 females.
• 2.2. Significant differences have been noted with age. In neonates, the lowest values of total proteins, glucose, creatinine, urea, AST, ALT and iron have been noted; the highest ones have been seen for cholesterol, alkaline phosphatase, calcium and phosphorus.
• 3.3. With regard to sex, raised values of glucose, urea, alkaline phosphatase and ALT, and lowered values of cholesterol, have been noted in juvenile females compared with males of the same age.
• 4.4. In adult females, higher levels of urea and cholesterol and lower levels of glucose, triglycerides and natrium have been recorded compared with males.
• 5.5. With sex and age, no significant changes have been found in the levels of GGT, magnesium, chlorides and copper.
• 6.6. Out findings are discussed with those abstracted from the literature for related species.

     

The influence of calcium and magnesium on sea bass (Dicentrarchus labrax) intestinal brush border membrane purification and activity

• 1.1. The activity of brush border enzymes (alkaline phosphatase, maltase, sucrase, trehalase, leucine amino peptidase) was higher in purified membranes prepared with calcium. The contamination of these membranes with basolateral membranes was also lower (1.27 for Na-K-ATPase activity ratio).
• 2.2. The extraction of brush border lipids was carried out according to Folch adapted method. Two dimensional thin layer chromatography was used to separate the phospholipidic fractions. Fatty acids of phospholipids were analysed using gas chromatography after acid transmethylation (column SP 2330).
• 3.3. Phospholipids are composed of phosphatidylcholine (PC: 33%), phosphatidylethanolamine (PE: 30%), sphingomyeline (SM: 21%), phosphatidylserine (PS: 14%) and phosphatidylinositol (PI: 2%). 4. PC, PE and PS are characterized by high levels of unsaturated fatty acids (monounsaturated MUFA: 21.5% and polyunsaturated PUFA: 34.9%). The most abundant PUFA belong to the (n-3) family [18:3 (n-3), 20:5 (n-3) and 22:6 (n-3)].
• 4.5. Fatty acids from sphingomyelin of purified membranes have low proportions of PUFA (13.5%) but higher proportions of MUFA (39.5%).
• 5.6. No specific differences were found between calcium and magnesium prepared membranes.
• 6.7. The low content in LPC and the absence of LPE confirmed the absence of major structural lipids transformation during the membrane purification with calcium or magnesium.
• 7.8. Glycine transport was measured during 10 sec at different temperatures using the rapid filtration technique. Glycine transport was higher with Na⁺ than with K⁺. In the presence of Na⁺, this transport increases with temperature.
• 8.9. Arrhenius curves were mono phasic without obvious breakpoint and indicated no phase transition in the lipid bilayer.
• 9.10. A significant Na⁺ dependent glycine transport has been characterized at low temperatures (0°C) which suggests a possible role of membrane polyunsaturated fatty acids in the control of glycine transport.

     

Plasma chemistry of rockhopper (Eudyptes crestatus), magellanic (Spheniscus magellanicus) and gentoo (Pygoscelis papua) wild penguins in relation to moult

• 1.1. Both the post-moult, rockhopper (Eudyptes crestatus) and magellanic penguins (Spheniscus magellanicus) had significantly lower plasma total protein, albumin, urate, iron and potassium and higher alkaline phosphatase activity than pre-moult birds. In addition creatinine, conjugated bilirubin and inorganic phosphate in the magellanics; globulin, urate, calcium, alanine and aspartate transaminases in the rockhoppers were significantly decreased.
• 2.2. There were significant differences in plasma bicarbonate, inorganic phosphate, alkaline phosphatase and iron concentrations between non-moulting adult and post-moult gentoo penguin (Pygoscelis papua) chicks.
• 3.3. Absence or scarcity of the preferred nutrient requirement during the period preceding moulting could threaten the survival of any of the species, particularly of those of narrow dietary speciality.

     

Vascular Endothelial Receptor Tyrosine Phosphatase: Identification of Novel Substrates Related to Junctions and a Ternary Complex with EPHB4 and TIE2,

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Highlights

• •Identification of the substrates profile of the endothelial phosphatase VE-PTP.
• •A large fraction of VE-PTP substrate candidates (29%) is cell junction related.
• •Tie-2 and EPHB are substrates which associate as ternary complex with VE-PTP.

     

In vitro Ca deposition by rat matrix vesicles: Is the membrane association of alkaline phosphatase essential for matrix vesicle-mediated calcium deposition?

• 1.1. Phosphatidylinositol phospholipase C (PI-PLC) treatment of rachitic rat matrix vesicles (MVs) released about 80% of membrane-bound alkaline phosphatase (ALP), AMPase, PPiase into the media.
• 2.2. About 20% hydrolytic activity was not released from MV membranes by PI-PLC treatment.
• 3.3. SDS-polyacrylamide gel electrophoresis and Western blot analysis showed only one immunoreactive protein corresponding to the molecular weight of ALP present in the soluble fraction after PI-PLC treatment.
• 4.4. The specific activity of the released ALP was at least 5-fold higher than the residual activity.
• 5.5. After PI-PLC treatment, MVs also demonstrated an 80% reduction of AMP- or βGP-dependent calcium deposition.
• 6.6. The soluble fraction containing 80% of ALP activity was unable to support calcium deposition. The mixing of the soluble and insoluble fractions after PI-PLC treatment failed to fully restore calcium-depositing activity.

     

Seasonal variation of phosphatase activity in the hepatopancreas of the snail Helix pomatia L.

• 1.1. Body weight, the weight of the hepatopancreas, protein content in the hepatopancreas and phosphatase activity at pH 8.5 in the hepatopancreas are great in spring and summer, and decrease during autumn and winter.
• 2.2. Phosphatase activity at pH4.5 is the same throughout the year.
• 3.3. Participation of acid phosphatases in extracellular and intracellular digestion and participation of alkaline phosphatases in food resorption and calcium deposition are postulated.

     

Purification of glycosylphosphatidylinositol-anchoring aminopeptidase in from the plasma membrane of larval midgut epithelial cells of the silkworm,Bombyx mori

• 1.1. Aminopeptidase N was selectively released from larval midgut of silkworm, Bombyx mori, by phosphatidylinositol-specific phospholipase C, and purified to a homogeneous state by ion exchange, gel filtration. Con A-Sepharose and 4-aminobenzyl phosphonic acid-agarose column chromatographies.
• 2.2. The purified aminopeptidase N preparation showed 190.8 U/mg of specific activity. Its molecular weight was estimated to be around 100 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
• 3.3. Purified aminopeptidase N molecule preferentially hydrolyzed Leu-, Ala- and Met-p-nitroanilide as substrates. Especially, Leu-p-nitroanilide proved to be the best substrate for aminopeptidase N from larval midgut of silkworm.
• 4.4. By treatment with phosphatidylinositol-specific phospholipase C, two other hydrolases, alkaline phosphatase and alkaline phosphodiesterase I, were also solubilized from silkworm midgut.

     

Redundancy and Complementarity between ERAP1 and ERAP2 Revealed by their Effects on the Behcet's Disease-associated HLA-B*51 Peptidome,

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Highlights

• •HLA-B*51 and ERAP1, but not ERAP2, are risk factors for Behçet's disease.
• •The HLA-B*51 peptidome and the effects of ERAP1 and ERAP2 on it are analyzed.
• •ERAP1 and ERAP2 alter multiple features of the HLA-B*51 peptidome in distinct ways.
• •Both enzymes act independently with complementary and partially redundant functions.