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)

In cultured amniotic cells from fetuses with Edward's syndrome (trisomy 18), the activities of two protein phosphatases, alkaline phosphatase and phosphotyrosine phosphatase, were measured. Comparison with normal fetal cells showed a different behavior for each enzyme. Alkaline phosphatase was significantly lowered while phosphotyrosine phosphatase remained at normal levels. The interest of these enzyme assays in the screening procedure of this severe chromosome defect is discussed.
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PMID:Alkaline phosphatase and phosphotyrosine phosphatase activities of cultured amniotic cells with trisomy 18. 130 52

We developed an assay to measure at acid pH the phosphotyrosine phosphatase activity in sera from patients with prostatic cancer. The method used quantifies the inorganic phosphate liberated from phosphotyrosine after incubation with serum, followed by the deproteinization of the reaction mixture. A high acid phosphatase (EC 3.1.3.2) activity towards phosphotyrosine was observed in all sera from patients with increased activity of prostatic acid phosphatase. This activity represented 96% of prostatic acid phosphatase and 77% of total acid phosphatase activities. Moreover, it was correlated (r = 0.91) with the amount of serum prostatic acid phosphatase determined by radioimmunoassay. When serum acid phosphatase activity was measured on several phosphorylated substrates, preferential hydrolysis was demonstrated for those in which the phosphate group was esterified on an aromatic ring rather than those presenting an aliphatic chain. Among phosphoamino acids, only phosphotyrosine was a good substrate, with little or no activity observed with phosphoserine and phosphothreonine. Human seminal plasma and partially purified prostatic acid phosphatase, tested for their activity on some of these substrates, gave similar results. On the other hand, sera from patients with above-normal alkaline phosphatase activity and no prostatic disease showed little or no activity on phosphotyrosine at both acid and alkaline pH values. Evidence is presented that the prostatic acid phosphatase in serum is a specific phosphotyrosine acid phosphatase.
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PMID:Prostatic acid phosphatase in serum of patients with prostatic cancer is a specific phosphotyrosine acid phosphatase. 169 55

Two highly sensitive, nonradiolabeled assays for protein phosphotyrosine phosphatase (PTPase) have been developed. The first assay is based on the use of chemically synthesised phosphotyrosine-containing peptides that can be separated from the dephosphorylated peptide products by HPLC. In this assay, partially purified placental PTPase 1B dephosphorylated three dodecaphosphopeptides (corresponding to insulin receptor autophosphorylation sites at positions PY1146, PY1150, and PY1151) with approximately equal affinity (Km 1.3-2.5 microM), indicating that PTPase 1B shows no distinct preference for the site of dephosphorylation in these peptides. The second assay employs either a phosphopeptide or an autophosphorylated tyrosine kinase domain immobolized on microtiter plate wells. After reaction with PTPase, the remaining unconverted phosphosubstrate is detected in an ELISA using anti-phosphotyrosine antibodies. The latter assay was used to monitor PTPase activity during purification procedures and for characterizing PTPases. Modulation of PTPase activity by orthovanadate, heparin, Zn2+, and EDTA gave similar results in both assays. The immobilized autophosphorylated IR tyrosine kinase domain was a poor substrate for bovine liver alkaline phosphatase and seminal fluid acid phosphatase. The second assay also offers the potential for comparing PTPase activity toward several autophosphorylated tyrosine kinase domains, including those of the insulin, epidermal growth factor, and platelet-derived growth factor receptors.
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PMID:Two nonradioactive assays for phosphotyrosine phosphatases with activity toward the insulin receptor. 181 86

Dehydroepiandrosterone (DHEA) treatment is effective in preventing or delaying the onset of various genetic and induced disorders of mice and rats. Associated with the beneficial therapeutic effects exerted by action of this steroid is the development of hepatomegaly. To determine whether the changes associated with hepatomegaly also involve alterations in activities of tissue enzymes, we evaluated the effects of DHEA (0.45% in food, w/w) on hepatic protein kinases, phosphatases, and lipogenic enzymes in mice of various strains. The rates of fatty acid and cholesterol syntheses also were evaluated. DHEA administration resulted in profound changes in the sodium dodecylsulfate-polyacrylamide gel electrophoresis patterns of endogenous radiophosphorylated proteins obtained by incubation of liver homogenates with (gamma-32P]ATP. These changes were dependent upon the medium used for homogenization. Thus, when homogenates of liver tissue of DHEA-treated mice were prepared in Tris buffer containing sucrose (0.25 M) there was a marked decrease in phosphorylation of the proteins of relative molecular weight approximately 116,000 (Mr approximately 116,000), approximately 82,000, approximately 80,000, approximately 58,000, approximately 56,000, approximately 48,000, approximately 34,000, and approximately 31,000 compared with controls. With liver homogenates of DHEA-treated mice prepared in Tris buffer alone, there was a marked increase in phosphorylation of the proteins of Mr approximately 70,000, approximately 49,000, approximately 34,000, approximately 31,000, and 28,000 compared with controls. Moreover, the specific activity of kinases for endogenous protein acceptors in liver of control mice was higher than that in liver of DHEA-treated animals. The specific activities of casein kinase, cAMP-dependent protein kinase, and cGMP-dependent protein kinase remained unchanged with DHEA treatment, but the specific activity of histone kinase was increased approximately 30%. Long-term administration of DHEA also was associated with increases in the specific activities of liver AMPase and GTPase (approximately two times), but not of other nucleotidases, alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, or phosphotyrosine phosphatase. The activity of hepatic NADP-linked malic enzyme was increased significantly (two to three times) by DHEA treatment of female mice of three different strains, but was unchanged in male C57BL/6 mice. The specific activities of hepatic glucose-6-phosphate dehydrogenase, NADP-linked isocitrate dehydrogenase, and ATP-citrate lyase were not affected significantly by DHEA treatment of mice. The rate of hepatic lipogenesis, determined by incorporation of tritium from 3H2O into fatty acids, was decreased approximately 70% in DHEA-treated mice, while the rate of cholesterol synthesis was increased approximately 44% compared with controls.
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PMID:Dehydroepiandrosterone feeding and protein phosphorylation, phosphatases, and lipogenic enzymes in mouse liver. 215 82

The activities of alkaline phosphatase and phosphoamino acid phosphatases were measured in normal and cancerous regions of the human larynx. For each larynx, alkaline phosphatase and phosphotyrosine phosphatase activities were higher in the tumor than in the corresponding normal tissue. Phosphothreonine and phosphoserine phosphatase activities were relatively low and there were no consistent trends. The increased alkaline phosphatase activity in the tumors supports histological observations that ossification of cartilage seems to occur at the site of invasion; the phosphatase acting on phosphotyrosine could serve as a regulator of cell differentiation during tumorigenesis.
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PMID:Alkaline phosphatase and phosphoamino acid phosphatases in normal and cancerous tissues of the human larynx. 231 Jun 11

A partially purified bovine cortical bone acid phosphatase, which shared similar characteristics with a class of acid phosphatase known as tartrate-resistant acid phosphatase, was found to dephosphorylate phosphotyrosine and phosphotyrosyl proteins, with little activity toward other phosphoamino acids or phosphoseryl histones. The pH optimum was about 5.5 with p-nitrophenyl phosphate as substrate but was about 6.0 with phosphotyrosine and about 7.0 with phosphotyrosyl histones. The apparent Km values for phosphotyrosyl histones (at pH 7.0) and phosphotyrosine (at pH 5.5) were about 300 nM phosphate group and 0.6 mM, respectively, The p-nitrophenyl phosphatase, phosphotyrosine phosphatase, and phosphotyrosyl protein phosphatase activities appear to be a single protein since these activities could not be separated by Sephacryl S-200, CM-Sepharose, or cellulose phosphate chromatographies, he ratio of these activities remained relatively constant throughout the purification procedure, each of these activities exhibited similar thermal stabilities and similar sensitivities to various effectors, and phosphotyrosine and p-nitrophenyl phosphate appeared to be alternative substrates for the acid phosphatase. Skeletal alkaline phosphatase was also capable of dephosphorylating phosphotyrosyl histones at pH 7.0, but the activity of that enzyme was about 20 times greater at pH 9.0 than at pH 7.0. Furthermore, the affinity of skeletal alkaline phosphatase for phosphotyrosyl proteins was low (estimated to be 0.2-0.4 mM), and its protein phosphatase activity was not specific for phosphotyrosyl proteins, since it also dephosphorylated phosphoseryl histones. In summary, these data suggested that skeletal acid phosphatase, rather than skeletal alkaline phosphatase, may act as phosphotyrosyl protein phosphatase under physiologically relevant conditions.
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PMID:Phosphotyrosyl-specific protein phosphatase activity of a bovine skeletal acid phosphatase isoenzyme. Comparison with the phosphotyrosyl protein phosphatase activity of skeletal alkaline phosphatase. 258 Aug 26

Isolated bone cells in culture contain an enzyme capable of hydrolyzing the phosphate ester of phosphotyrosine. This enzyme, which we have termed phosphotyrosine phosphatase, has not previously been reported in bone. Some of its characteristics include: 1) maximum activity near physiological pH, 2) a Km for substrate of 52 microM, 3) marked inhibition by the phosphate analog vanadate ion, 4) activity correlation with bone cell alkaline phosphatase, and 5) regulation by bone target hormones. Data obtained with vanadate ion support the contention that this enzyme may play a role in the regulation of bone cell growth.
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PMID:Bone cell phosphotyrosine phosphatase: characterization and regulation by calcitropic hormones. 258 72

We used embryonic skeletal cartilage known to have high levels of alkaline phosphatase activity to determine whether growing cartilage has phosphotyrosine phosphatase activity and phosphotyrosinyl histone phosphatase activity at physiologic pH. Embryonic chick pelvic cartilage and fetal pig scapular growth-plate cartilage were assayed using phosphotyrosine as substrate at pH 7.5 and the amount of tyrosine generated measured. Both cartilage models had Km for phosphotyrosine between 6 to 24 mus mol/L. Phosphotyrosine phosphatase activity correlated with alkaline phosphatase activity as assessed by (1) distribution of histologic staining for alkaline phosphatase within the cartilages, (2) hormonal stimulation of cartilage alkaline phosphatase activity in vitro, (3) comparison of alkaline phosphatase and phosphotyrosine phosphatase activities in the presence of known inhibitors (vanadate, levamisole, homoarginine, and zinc), and (4) assaying chick epiphyseal cartilage alkaline phosphatase purified to homogeneity for phosphotyrosine phosphatase activity. Areas of cartilage with elevated alkaline phosphatase activity also had raised phosphotyrosine phosphatase activity. Triiodothyronine, a known stimulator of cartilage alkaline phosphatase, increased chick cartilage alkaline phosphatase activity 88% and phosphotyrosine phosphatase activity 106%, and stimulated porcine growth-plate cartilage alkaline phosphatase activity 91% and phosphotyrosine phosphatase activity 145% after 3 days of in vitro incubation. Each of the inhibitors block alkaline phosphatase and phosphotyrosine phosphatase activities. The purified alkaline phosphatase had a Km for phosphotyrosine of 18 mus mol/L and Vmax of 5700 nmol tyrosine/mg protein/h, which is well over 1000-fold higher than the phosphotyrosine phosphatase activity found in the above preparations of pelvic and scapular cartilage.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phosphotyrosine and phosphoprotein phosphatase activity of alkaline phosphatase in mineralizing cartilage. 298 79

The activities of acid and alkaline phosphatases and phosphotyrosine, phosphoserine and phosphothreonine phosphatases were measured in Friend murine erythroleukaemic (MEL) cells. The effects of treating the cells with dimethyl sulphoxide (DMSO), an inducer of differentiation, were examined. In untreated cells alkaline phosphatase activity was undetectable, though there were significant amounts of acid phosphatase (76 +/- 15 mU/mg protein) and phosphotyrosine phosphatase (16 +/- 0.9mU/mg protein); phosphoserine and phosphothreonine phosphatase activities (9 +/- 0.4 and 7 +/- 0.6mU/mg protein, respectively) were lower than for phosphotyrosine phosphatase. Addition of 1 or 2% DMSO to the culture medium resulted in the expected cell death within 2 weeks. With 0.5% DMSO, cells remained viable for at least 8 weeks, but while some appeared to have smaller nuclei and retained their rounded appearance, others became fibroblastic within several days and adhered to the culture vessel. The treated cells which had kept their morphology showed no difference in acid phosphatase activities as compared with untreated controls; phosphotyrosine phosphatase was lower (9 +/- 0.8mU/mg protein) and phosphoserine and phosphothreonine phophatases higher (11 +/- 0.5 and 10 +/- 0.4mU/mg protein, respectively) than in the controls. The Km values for p-nitrophenyl phosphate were similar in untreated and treated cells (0.069 and 0.068mM, respectively); for phosphotyrosine the Km value was lower in the treated cells (0.97mM) than in the controls (1.9mM).
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PMID:Acid phosphatase and phosphoamino acid phosphatases in murine erythroleukaemic cells. 298 19

Rat prostatic acid phosphatase (rPAP; orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) was expressed in the baculovirus expression vector system. Recombinant protein was secreted into the medium at a high yield by infected insect cells, which were cultured at high density in a 30-liter bioreactor allowing high oxygen content for rapidly growing cells. About 20% of the cell protein produced was rPAP. Partial sequence determination of the N terminus of the purified recombinant secreted protein revealed identity to the native secreted protein, showing that the signal peptide is recognized and properly cleaved in insect cells. The enzyme was purified by using L-(+)-tartrate affinity chromatography. The purified protein had a high specific activity of 2620 mumol.min-1.mg-1 with p-nitrophenyl phosphate at the substrate, and it also showed phosphotyrosine phosphatase activity. The molecular mass of the recombinant rPAP was 155 kDa. Two subunits of 46 kDa and 48 kDa could be detected in SDS/PAGE, but only one subunit of 41 kDa was present after digestion with N-glycosidase. The active enzyme is a trimer of subunits differing only in glycosylation. When recombinant rPAP was crystallized with polyethylene glycol 6000 as the precipitant, the crystals were trigonal (space group P3(1)21) with cell dimensions a = 89.4 A and c = 152.0 A. The observed diffraction pattern extends to a resolution of at least 3 A.
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PMID:Rat acid phosphatase: overexpression of active, secreted enzyme by recombinant baculovirus-infected insect cells, molecular properties, and crystallization. 843 88


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