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 membrane fraction from calf thymocytes was used to investigate molecular and catalytic properties of membrane-bound alkaline phosphatase (ortho-phosphoric-monoester phosphohydrolase EC 3.1.3.1). The principal findings were: 1. Solubilization of membranes with the non-ionic detergent Triton X-100 increases alkaline phosphatase activity by 30-40%. The enzyme activity elutes in a single peak (Stokes' radius = 7.7 nm) after chromatography in Sepharose 6B in the presence of Triton X-100. The activity also sediments as a single component of approx. 6.4 S during centrifugation in sucrose gradients containing Triton X-100. 2. Ion-exchange chromatography and isoelectric focusing in the presence of Triton X-100 indicate substantial charge heterogeneity. Two overlapping bands, a peak at pH 5.92 with a pronounced shoulder at pH 5.29, are apparent by isoelectric focusing. 3. The pH optimum for hydrolysis of p-nitrophenylphosphate (pNPhP) by the undissolved enzyme(s) is 9.57. Half-maximal activity occurs at pH 8.65 and ph 10.45. Triton X-100 has no effect on the pH profile. 4. Catalytic activity is affected by amines, especially analogues of ethanolamine. Diethanolamine exerts a unique stimulatory effect, but does not change the pH dependency. Increasing the concentration of diethanolamine from 0 to 1 M causes a 6-fold increase in Km and a 10-fold increase in the rate of hydrolysis of pNPhP. Glycine is inhibitory. 5. EDTA causes an irreversible loss of activity with t1/2 (1 mM EDTA, pH 8.2, 23 degrees C) = 3.5 h. Optimal activity is achieved in 0.1--1.0 mM Mg2+, although this does not cause the degree of activation reported to occur with the purified enzymes. Other divalent ions are inhibitory. Concentrations required to reduce activity to 50% of control are: Zn2+, 4.0 muM (no added Mg2+) and 30 muM (in the presence of 1 mM Mg2+); Mn2+, 0.25 mM (+/- Mg2+); Ca2+, 20 mM (+/- Mg2+). 6. Monovalent cations have little effect on activity. In the absence of added Mg2+, 50--150 mM Na+ is partially inhibitory, but markedly less so in the presence of 1 mM Mg2+. K+ has no significant effect. 7. Of the substrates tested, pNPhP (Km = 44 muM) was most rapidly hydrolyzed. Other substrates (rate relative to pNPhP) were alpha-naphthylphosphate (0.79), 2'-AMP (0.80), 5'-AMP (0.70), 3'-AMP (0.63), alpha-glycerophosphate (0.47) and glucose 6-phosphate (0.35). Phosphodiesterase activity was less than or equal to 10% of the phosphomonoesterase activity (for pNPhP) as evidenced by the lack of hydrolysis of bis(p-nitrophenyl)-phosphate and cyclic 3',5'-AMP. The ability of these substances to inhibit hydrolysis of pNPhP reflected their capacity as substrates, i.e. the most inhibitory were the most rapidly hydrolyzed.
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PMID:Calf thymus alkaline phosphatase. I. Properties of the membrane-bound enzyme. 1 42

4-Nitrophenyl and 2-napthyl monoesters of phenylphosphonic acid have been synthesized, and an enzyme catalyzing their hydrolysis was resolved from alkaline phosphatase of a commerical calf intestinal alkaline phosphatase preparation by extensive ion-exchange chromatography, chromatography on L-phenylalanyl-Sepharose with a decreasing gradient of (NH4) 2SO4, and gel filtration. Detergent-solubilized enzyme from fresh bovine intestine was purified after (NH4)2SO4 fractionation by the same technique. The purified enzyme is homogeneous by polyacrylamide gel electrophoresis and sedimentation equilibrium centrifugation. It has a molecular weight of 108,000, contains approximately 21% carbohydrate, and has an amino acid composition considerably different from that reported from alkaline phosphatase from the same tissue. The homogeneous intestinal enzyme, an efficient catalyst of phosphonate ester hydoolysis but not of phosphate monoester hydrolysis, was identified as a 5'-nucleotide phosphodiesterase by its ability to hydrolyze 4-nitrophenyl esters of 5'-TMP but not of 3'-TMP. Also consistent with this identification was the ability of the enzyme to hydrolyze 5'-ATP to 5'-AMP and PPi, NAD+ to 5'-AMP and NMN, TpT to 5'-TMP and thymidine, pApApApA to 5'-AMP, and only the single-stranded portion of tRNA from the 3'-OH end. Snake venom 5'-nucleotide phosphodiesterase also hydrolyzes phosphonate esters, but 3'-nucleotide phosphodiesterase of spleen and cyclic 3',5'-AMP phosphodiesterase do not. Thus, types of phosphodiesterases can be conveniently distinguished by their ability to hydrolyze phosphonate esters. As substrates for 5'-nucleotide phosphodiesterases, phosphonate esters are preferable to the more conventional esters of nucleotides and bis(4-nitrophenyl) phosphate because of their superior stability and ease of synthesis. Furthermore, the rate of hydrolysis of phosphonate esters under saturating conditions is greater than that of the conventional substrates. At substrate concentrations of 1 mM the rates of hydrolysis of phosphonate esters and of nucleotide esters are comparable and both superior to that of bis(4-nitrophenyl) phosphate.
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PMID:Hydrolysis of phosphonate esters catalyzed by 5'-nucleotide phosphodiesterase. 17 Sep 64

Urinary cyclic adenosine 3'5' monophosphate (AMP) excretion has been determined by radioimmunoassay in children with rickets and in control children. Cyclic AMP was greatly increased in children with rickets. The excretion of cyclic AMP correlated significantly with parathyroid hormone levels (PTH) and alkaline phosphatase, but not with age, calcaemia and serum inorganic phosphate. Calcium infusion led to a decrease in the excretion of cyclic AMP. The data are consistent with following hypothesis. During vitamin D deficiency, high PTH levels can increase the renal excretion of cyclic AMP. The effects of PTH on bone resorption fail to maintain the levels of serum calcium due to the lack of vitamin D. The mechanism by which the secondary hyperparathyroidism develops during vitamin D deficiency remains to be investigated.
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PMID:Urinary excretion of adenosine 3'5' monophosphate in vitamin D deficiency. 17 92

Short-chain fatty acids, such as propionic, n-butyric, n-butyric, n-valeric, isovaleric, n-caproic, and n-caprylic acids, induce alkaline phosphatase activity in cultured mammalian cells. Long-chain fatty acids have no similar effects. With B-6 cells (mouse X Chinese hamster cell hybrids), n-butyrate at 2 to 5 mM exhibits the greatest activity. Induction begins exponentially about 24 hours after addition of the fatty acid and continues over 48 hours. Studies on the inducing activity-structure relationship revealed the necessity of a carboxyl and an ethyl or longer alkyl group. n-Butyrate shows a marked synergistic action of induction when added along with other types of inducers: adenosine 3':5'-cyclic monophosphate (cAMP) or 5-bromodeoxyuridine (BrdU). Treatment of other cell lines with either n-buryrate, cAMP, or BrdU revealed a cell-type specific response pattern of alkaline phosphatase. The biological significance of this effect of short-chain fatty acids is discussed.
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PMID:Induction by short-chain fatty acids of alkaline phosphatase activity in cultured mammalian cells. 17 33

Soluble adenylate cyclase [EC 4.6.1.1] accumulates in the culture medium of exponentially growing Bordetella pertussis (300-900 pmol of cAMP formed/min per ml of 24 hr culture supernatant). In addition, there is an extracytoplasmic adenylate cyclase which enables the intact organisms to form [32P] cAMP (adenosine 3':5'-cyclic monophosphate) from exogenous [alpha-32P] ATP (200-1200 nmol of cAMP formed/min per g wet weight of cells) and which comprises 20-45% of the total adenylate cyclase activity. In contrast, only 1.7 and 2.4% of the total cell malate dehydrogenase [EC 1.1.1.37] and alkaline phosphatase [EC 3.1.3.1], respectively, are detectable in the intact cell. Trypsin treatment of intact organisms destroys 96% of the extracytoplasmic adenylate cyclase, but does not reduce the total cell malate dehydrogenase or a small pool of intracellular adenylate cyclase. Four compartments of adenylate cyclase in B. pertussis are proposed; (A) soluble enzyme in the culture supernatant (up to 20% of the total activity); (B) enzyme associated with intact cells and measurable without cell disruption (20-45%); (C) extracytoplasmic enzyme sensitive to trypsin, but not measurable in intact cells at standard substrate concentrations (40-60%); and (D) intracellular enzyme (7-9%). In comparison with previously studied bacterial adenylate cyclases, the extracytoplasmic location appears to be unique to the B. pertussis enzyme.
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PMID:Extracytoplasmic adenylate cyclase of Bordetella pertussis. 18 May 29

Two metabolically distinct types of bone cell populations were isolated from mouse calvaria by a repetitive digestive procedure with a mixture of collagenase and trypsin. Cells released early in the digestion showed approximately two-fold increases in cAMP when treated with either parathormone or calcitonin. These populations were denoted CT type. Later eluting cells showed larger parathormone-induced increases in cAMP but did not respond to calcitonin. These populations were denoted PT type. Six metabolic and enzymatic activites were measured in the two types of populations: acid and alkaline phosphatases, hyaluronate synthesis, citrate decarboxylation, prolyl hydroxylase, and general protein synthesis. Although each of these activites was present in both cell types, the basal levels of acid phosphatase and hyaluronate synthesis were higher in the CT cells, whereas alkaline phosphatase, citrate decarboxylation, and prolyl hydroxylase were higher in te PT cells. Parathormone stimulated acid phosphatase and hyaluronate synthesis by 100-200% only in the CT cells; in inhibited alkaline phosphatase, citrate decarboxylation, and prolyl hydroxylase by 75-90% only in the PT cells. Calcitonin alone had no effect on any of these activities other than cAMP production, but in inhibited the action of parathormone in the CT cells. The sensitivities, time courses of development,and magnitudes of these hormonal effects were similar to those observed previously in intact calvaria, indicating that the isolated cell system is a reliable model for the study of bone metabolism. Based on the metabolic responses of the cells, we postulate that the CT type of populations is enriched in osteoclasts and, possibly, osteocytes, and the PT type of population is enriched in osteoblasts.
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PMID:Biochemical characterization with parathormone and calcitonin of isolated bone cells: provisional identification of osteoclasts and osteoblasts. 18 58

Myocardial acidic non-histone nuclear proteins (NHPs) contain endogenous protein kinase activity. Phosphocellulose chromatography of purified NHPs identifies nine separate peaks of protein kinases which can phosphorylate both endogenous and exogenous substrates to a variable degree; endogenous NHPs are the best substrates. Cyclic AMP-stimulated protein kinase induced phosphorylation of endogenous and exogenous substrates; the extent of this stimulation varied according to the protein kinase fraction and substrate used. Cyclic AMP also enhanced NHP-induced stimulation of RNA polymerase activity. This enhancement was dependent on protein kinase-induced phosphorylation of NHPs since it was prevented by alkaline phosphatase pretreatment. It is concluded that nuclear protein kinases regulate myocardial RNA synthesis by enhancing phosphorylation of NHPs and that this regulation is under cyclic AMP control.
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PMID:Adenosine 3',5'-monophosphate-dependent protein kinases of myocardial non-histone nuclear proteins. 19 45

Either vitamin D3 (or 1 alpha,25--(OH)2-D3) or hydrocortisone (HC) stimulated phosphate accumulation by organ-cultured embryonic chick duodenum. In combination, these two steroids stimulated phosphate uptake synergistically. Phosphate accumulation appeared to be independent of other vitamin D3-stimulated processes: CaBP concentration, cAMP concentration, or alkaline phosphatase activity. L-phenylalanine, a reported alkaline phosphatase inhibitor, when added to the culture medium progressively inhibited either D3- or HC-stimulated phosphate uptake subsequent to culture, but did not inhibit the synergistic action. Under these conditions L-phenylalanine had no consistent effect on alkaline phosphatase activity but unexpectedly, greatly inhibited vitamin D3-stimulated CaBP concentration, but only in the absence of HC. Some limited suggestion of an intestinal phosphoprotein sensitive to either vitamin D3 or HC was observed.
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PMID:Hydrocortisone and vitamin D3 stimulation of 32Pi-phosphate accumulation by organ-cultured chick embryo duodenum. 22 77

Indices of calcium and phosphorus metabolism were studied in 3 children with osteopetrosis before and after infusion of bovine parathyroid hormone extract. Basal plasma concentrations of calcium, alkaline phosphatase and 25-hydroxy vitamin D tended to be low. Plasma immunoreactive PTH levels were at the upper normal range in two patients. A marked increase in urinary cyclic AMP in all patients was solely due to an increase in the nephrogenous cAMP. After vitamin D treatment urinary cAMP was essentially unchanged with the same preponderance of nephrogenous cAMP. Following PTH infusion plasma cAMP showed a brisk rise. There was also a prompt rise in urinary cAMP and a distinct decrease in the calcium to sodium clearance ratio indicating increased calcium reabsorption. Phosphaturic effect was only observed when PTH was given in the highest dose level. The findings are consistent with a state of low grade hyperparathyroidism which could not be related to the plasma levels of 25-hydroxy vitamin D or calcium.
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PMID:Acute response of parathyroid hormone in congenital osteopetrosis. 23 56

Rat small bowel was perfused in vivo and ex vivo in the absence of biliary and pancreatic secretion. Intraluminal release of sucrase, alkaline phosphatase, aminopeptidase and enterokinase was significantly increased after administration of PG E1 and E2 1 and 5 microgram/kg. This suggests a direct stimulation of the intestinal mucosa, which might be mediated through cyclic AMP; dibutyryl cAMP significantly stimulates intraluminal release of proteins, sucrase and enterokinase.
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PMID:Prostaglandins E1 and E2 stimulate release of intestinal brush border enzymes. 90 72


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