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)

Periostea were dissected from 1-2 weeks old rabbit calvaria and folded around decalcified and extracted bovine dentin matrix slices (DMS). The cocultures were grown in serum-containing medium supplemented with beta-glycerophosphate or other organic phosphate esters. [45Ca]-uptake measurements indicated that the DMS calcified. Initiation of the calcification process was associated with alkaline phosphatase activity and could be prevented by adding the inhibitor L-levamisole to the culture medium. Using [32P]-adenosine-monophosphate as a substrate for phosphatase activity it was demonstrated that very little, if any, phosphate was utilized for the phosphorylation of higher molecular weight substances. The results suggest that over 99% of the phosphate produced was laid down in inorganic form. Further, it was noted that mineral deposition in the DMS was accompanied by the simultaneous inclusion of methylene blue and PAS-positive substances whose nature, origin and function remain to be determined. The results lend support to the theory that alkaline phosphatase is involved in the initiation of calcification processes by raising the local concentration of phosphate ions.
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PMID:Calcification of dentinal collagen by cultured rabbit periosteum: the role of alkaline phosphatase. 272 22

Several compounds were tested as inhibitors of the alkaline phosphatase (AlkPase) activity associated with the isolated brush border membrane of the tapeworm, Hymenolepis diminuta. Molybdate, arsenate, arsenite and beta-glycerophosphate (BGP) were competitive inhibitors of the hydrolysis of p-nitrophenyl phosphate, while levamisole and clorsulon were uncompetitive and mixed inhibitors, respectively. Molybdate was also a competitive inhibitor of the hydrolysis of BGP and 5'-adenosine monophosphate, and levamisole was an uncompetitive inhibitor of BGP hydrolysis. The apparent inhibitor constants (Ki') for molybdate and levamisole were virtually identical regardless of the substrate, and these data support the hypothesis that the AlkPase activity is represented by a single membrane-bound enzyme with low substrate specificity. Quinacrine, Hg2+, and ethylenediaminetetraacetate were also potent inhibitors of the AlkPase activity, but the mechanisms by which these latter three inhibitors function were not clear.
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PMID:Competitive, uncompetitive, and mixed inhibitors of the alkaline phosphatase activity associated with the isolated brush border membrane of the tapeworm Hymenolepis diminuta. 276 48

To investigate further the pathophysiology of rotavirus-induced diarrhea, changes in specific activities of eight relevant intestinal enzymes [alkaline phosphatase, thymidine kinase, lactase, maltase, sucrase, Na+,K+-adenosine triphosphatase (ATPase), adenylate and guanylate cyclases] were measured following infection of suckling mice with murine rotavirus (epizootic diarrhea of infant mouse strain) and compared with age-matched control mice. The concentration of lactose within the lumen of the gastrointestinal tract during infection was also measured. During the course of infection, activities of alkaline phosphatase and lactase decreased, whilst the activity of thymidine kinase increased. Precocious maturation profiles of sucrase and maltase enzymes were observed. No significant changes were detected in the activities of Na+,K+-ATPase or the adenylate and guanylate cyclases. These results are discussed in relation to existing and novel hypotheses on the pathogenesis of rotavirus-induced diarrhea.
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PMID:Intestinal enzyme profiles in normal and rotavirus-infected mice. 289 74

A method is reported for preparing surface (plasma) membranes from rat Sertoli cells. The procedure is based upon homogenization in hypotonic buffer, extraction in a two-phase system, and sedimentation through two sucrose density gradients. The purified membranes consist of large sheets of membrane. The identity and purity of the membranes was demonstrated by electron microscopy, enzyme markers, and functional activities associated with the membranes (binding of follicle-stimulating hormone [FSH] and production of cyclic adenosine 5'-monophosphate [cAMP]. Electron microscopy showed membranes with small fragments of cytoplasm attached to the inside of the membrane sheets. Marker enzymes for plasma membrane (5'-nucleotidase and alkaline phosphatase) showed more than 16- and 6-fold enrichment, respectively, and other enzymes showed that contamination by nuclei, mitochondria, endoplasmic reticulum, or cytosol was negligible. Binding of FSH was found to be specific, with KD 1.2 nM and the equivalent of 7500 sites per cell. This binding was enriched 20-fold compared to whole homogenate. Production of cAMP by membranes was increased by addition of FSH and by forskolin to the purified membranes in vitro.
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PMID:Plasma membranes from rat Sertoli cells: purification and properties. 310 2

The 2- and 8-azido trimer 5'-triphosphate photoprobes of 2-5A have been enzymatically synthesized from [gamma-32P]2-azidoATP and [alpha-32P]8-azidoATP by 2-5A synthetase from rabbit reticulocyte lysates. Identification and structural determination of the 2- and 8-azido adenylate trimer 5'-triphosphates were accomplished by enzymatic hydrolyses with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase. Hydrolysis products were identified by HPLC and PEI-cellulose TLC analyses. The 8-azido photoprobe of 2-5A displaces p3A4[32P]pCp from RNase L with affinity equivalent to p3A3 (IC50 = 2 X 10(-9) M in radiobinding assays). The 8-azido photoprobe also activates RNase L to hydrolyze poly(U) [32P]pCp 50% at 7 X 10(-9) M in core-cellulose assays. The 2- and 8-azido photoprobes and authentic p3A3 activate RNase L to cleave 28S and 18S rRNA to specific cleavage products at 10(-9) M in rRNA cleavage assays. The nucleotide binding site(s) of RNase L and/or other 2-5A binding proteins in extracts of interferon-treated L929 cells were investigated by photoaffinity labeling. Dramatically different photolabeling patterns were observed with the 2- and 8-azido photoprobes. The [gamma-32P]2-azido adenylate trimer 5'-triphosphate photolabels only one polypeptide with a molecular weight of 185,000 as determined by SDS gel electrophoresis, whereas the [alpha-32P]8-azido adenylate trimer 5'-triphosphate covalently photolabels six polypeptides with molecular weights of 46,000, 63,000, 80,000, 89,000, 109,000, and 158,000. Evidence that the photolabeling by 2- and 8-azido 2-5A photoprobes was highly specific for the p3A3 allosteric binding site was obtained as follows.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:2- and 8-azido photoaffinity probes. 1. Enzymatic synthesis, characterization, and biological properties of 2- and 8-azido photoprobes of 2-5A and photolabeling of 2-5A binding proteins. 324 13

A novel nucleotide, Ypp5'A2'p, has been purified through perchloric acid extraction of rat liver followed by DEAE-cellulose and ion pair high pressure liquid chromatographies. Y stands for an unknown compound, probably a nucleoside, whose sugar moiety is different to beta-D (deoxy) ribose. Treatment of Ypp5'A2'p with snake venom phosphodiesterase renders Yp and adenosine 2',5'-bisphosphate (pAp). After elimination of the terminal phosphate with alkaline phosphatase, the resulting nucleotide (Ypp5'A) yielded Yp and 5'-AMP when hydrolyzed by the phosphodiesterase. The following ultraviolet absorption spectral characteristics were determined at pH 7: Ypp5'A2'p (lambda max = 265 nm; A250/A260 = 0.76; A280/A260 = 0.79); Yp (lambda max = 279 nm; A250/A260 = 0.70; A280/A260 = 1.70). The molar extinction coefficient found for Yp at 280 nm was 20.6 x 10(3) M-1 cm-1.
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PMID:Rat liver contains a novel nucleotide, Ypp5'A2'p, related to adenosine 2',5'-bisphosphate. 343 33

Adenosine 2',5'-bisphosphate (pAp) is present in liver from 2-day-fasted rats, at a concentration of around 1 microM. pAp was obtained through perchloric acid extraction of the liver followed by two successive DEAE-cellulose chromatographies and an ion-pair high-pressure liquid chromatography. Both pAp extracted from liver and that obtained from a commercial source showed the same pattern of hydrolysis by alkaline phosphatase, i.e., more 5'-AMP than 2'-AMP was obtained as an intermediate of the reaction.
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PMID:Occurrence of adenosine 2',5'-bisphosphate in rat liver. 395 75

An enzyme that converts [3H, 32P]ATP, with a 3H:32P ratio of 1:1, to oligoadenylates with the same 3H:32P ratio was increased in plants following treatment with human leukocyte interferon or plant antiviral factor or inoculation with tobacco mosaic virus. The enzyme was extracted from tobacco leaves, callus tissue cultures, or cell suspension cultures. The enzyme, a putative plant oligoadenylate synthetase, was immobilized on poly(rI) . poly(rC)-agarose columns and converted ATP into plant oligoadenylates. These oligoadenylates were displaced from DEAE-cellulose columns with 350 mM KCl buffer, dialyzed, and further purified by high-performance liquid chromatography (HPLC) and DEAE-cellulose gradient chromatography. In all steps of purification, the ratio of 3H:32P in the oligoadenylates remained 1:1. The plant oligoadenylates isolated by displacement with 350 mM KCl had a molecular weight greater than 1000. The plant oligoadenylates had charges of 5- and 6-. HPLC resolved five peaks, three of which inhibited protein synthesis in reticulocyte and wheat germ systems. Partial structural elucidation of the plant oligoadenylates has been determined by enzymatic and chemical treatments. An adenylate with a 3',5'-phosphodiester and/or a pyrophosphoryl linkage with either 3'- or 5'-terminal phosphates is postulated on the basis of treatment of the oligoadenylates with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase and acid and alkaline hydrolyses. The plant oligoadenylates at 8 X 10(-7) M inhibit protein synthesis by 75% in lysates from rabbit reticulocytes and 45% in wheat germ cell-free systems.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Plant oligoadenylates: enzymatic synthesis, isolation, and biological activities. 399 78

The present studies were undertaken to determine the role, if any, of cyclic 3',5'-adenosine monophosphate (cyclic AMP) as a chemical inducer of rat liver alkaline phosphatase. Cholera enterotoxin, given intravenously to rats, led to a rapid rise in the activity of hepatic adenyl cyclase that was 7(1/2) times greater than control values in 6 h. Cyclic AMP levels were also significantly increased above control values while the activity of cyclic nucleotide phosphodiesterase was unchanged. Hepatic alkaline phosphatase activity was increased 5(1/2) times above control in 12 h, but its rise followed that of adenyl cyclase and cyclic AMP by several hours. Cycloheximide inhibited the rise of hepatic alkaline phosphatase but not that of adenyl cyclase. The administration of glucagon, a known stimulator of hepatic adenyl cyclase, and of dibutyryl cyclic AMP, led to similar striking increases in hepatic alkaline phosphatase activity. This alkaline phosphatase increase was blocked by the prior administration of cycloheximide. Bile duct ligation, a known stimulator of hepatic alkaline phosphatase activity, failed to produce any significant changes in adenyl cyclase or cyclic AMP. Concomitant treatment of rats with bile duct ligation and cholera enterotoxin or bile duct ligation and glucagon, had no additive effect on the increase in hepatic alkaline phosphatase activity, although the increase occurred earlier. These results suggest that: (a) cyclic AMP may act as an inducer of hepatic alkaline phosphatase: (b) the stimulation of hepatic alkaline phosphatase by cholera enterotoxin is mediated by cyclic AMP; (c) the rise in hepatic alkaline phosphatase following bile duct ligation is not mediated by cyclic AMP; (d) the same alkaline phosphatase in rat liver may be induced by two (or more) mechanisms, only one of which requires cyclic AMP.
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PMID:Alkaline phosphatase. Possible induction by cyclic AMP after cholera enterotoxin administration. 435 3

1. Radioactivity was incorporated into 5'-O-phosphoryladenylyl-(3'-5')-adenosine (pApA) on incubation with adenylate kinase and [gamma-(32)P]ATP. The corresponding triadenylate and tetra-adenylate reacted more slowly. 2. Only oligoadenylate with a terminal 5'-phosphate served as the substrate. 3. The product formed from pApA was shown to behave like 5'-O-pyrophosphoryladenylyl-(3'-5')-adenosine (ppApA) on hydrolysis with alkaline phosphatase, potassium hydroxide and hydrochloric acid. 4. The characteristics of the reaction indicated that it was catalysed by adenylate kinase, but the rate of phosphate transfer from ATP to pApA was about 0.01% of that in the typical reaction with AMP. 5. The reverse reaction between ADP and ppApA occurred readily, but no additional phosphorylation of ppApA (to give pppApA) could be demonstrated.
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PMID:The phosphorylation of 5'-oligoadenylic acids by adenylate kinase and adenosine triphosphate. 569 May 36


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