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

---

Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calmodulin, an activator protein in most calcium-dependent processes, was isolated to apparent homogeneity from the femurs of 1-day old chicks using phenyl-Sepharose and high performance liquid chromatography. The purified calmodulin was found to produce a 6-fold increase in the activity of alkaline phosphatase isolated from the same source. A Ca2+ concentration of 10(-5) M was required for the activation. Purification of alkaline phosphatase involved acetone precipitation, DEAE-Sephacel and Sephadex G-200 column chromatography. The enzyme was purified to 540-fold and had a specific activity of 10.75 U/mg protein.
...
PMID:The activation of chick alkaline phosphatase by calmodulin. 166 29

The small number of hair cells in auditory and vestibular organs severely impedes the biochemical characterization of the proteins involved in mechano-electrical transduction. By developing an efficient and clean "twist-off" method of hair bundle isolation, and by devising a sensitive, nonradioactive method to detect minute quantities of protein, we have partially overcome this limitation and have extensively classified the proteins of the bundles. To isolate hair bundles, we glue the saccular macula of the bullfrog to a glass coverslip, expose the tissue to a molten agarose solution, and allow the agarose to solidify to a firm gel. By rotating the gel disk with respect to the fixed macula, we isolate the hair bundles by shearing them at their mechanically weak bases. The plasma membranes of at least 80% of the stereocilia reseal. To visualize the proteins of the hair bundle, we covalently label them with biotin, separate them by SDS-PAGE, and transfer them to a charged nylon membrane. We can detect less than 500 fg of protein by probing the membrane with streptavidin-alkaline phosphatase and detecting the chemiluminescent product from the hydrolysis of the substrate 3-(4-methoxyspiro-(1,2-dioxetane-3,2'-tricyclo-[3.3.1. 1(3.7)]decan)-4-yl) phenyl phosphate (AMPPD). These techniques reveal a distinct constellation of proteins in and associated with hair bundles. Several proteins, such as calmodulin, calbindin, actin, tubulin, and fimbrin, have previously been described. A second class of proteins in the preparation appears to be derived from extracellular sources. Finally, several heretofore undescribed bundle proteins are identified and characterized by their membrane topology, subcellular localization, and glycosidase and protease sensitivities.
...
PMID:High-purity isolation of bullfrog hair bundles and subcellular and topological localization of constituent proteins. 170 75

The present paper reports immunohistological findings in porcine skin, which were obtained by use of mono- and polyclonal antihuman antibodies and either alkaline phosphatase anti-alkaline phosphatase (APAAP) or peroxidase (POX) technique. Epidermal staining was observed with antibodies to keratins (K 8.12, RSKE 60), filaggrin, and calmodulin (ACAM). Staining of connective tissue and vessels was achieved using antibodies to vimentin (V9(1)), collagen type IV, and fibronectin. In general, these antibodies gave a staining pattern similar to that of normal human skin. The similarities of immunoreactivity to poly- and monoclonal antihuman antibodies in porcine and human skin render porcine skin a reliable model in biomedical research.
...
PMID:Immunohistochemistry of porcine skin. 171 Aug 64

The activity of the eukaryotic elongation factor 2 (eEF-2)-specific Ca(2+)- and calmodulin-dependent protein kinase III (CaM PK III) is regulated by phosphorylation. The kinase can be inactivated by treatment with alkaline phosphatase and subsequently reactivated by endogenous protein kinase. This kinase can be substituted for by the catalytic subunit of cAMP-dependent protein kinase but not by casein kinase II. The purified kinase preparation contains only one protein as judged by gel electrophoresis. This protein has a molecular mass of approximately 90 kDa and an isoelectric point of 5.2. Reactivation of the eEF-2 kinase is associated with the phosphorylation of this protein. The amino acid sequence obtained from the 90-kDa protein reveals substantial homology with that of murine heat shock protein 86 (HSP 86) a member of the HSP 90-family. Conventional preparations of HSP 90 contain an inactive eEF-2 kinase that could be activated after dephosphorylation and phosphorylation by the catalytic subunit of cAMP-dependent protein kinase.
...
PMID:Phosphorylation regulates the activity of the eEF-2-specific Ca(2+)- and calmodulin-dependent protein kinase III. 188 75

To assess whether calcitonin exerts an influence on cartilage, three models of arthropathies in rabbits--representing three different modes of cartilage destruction--were used: (1) corticosteroid administration (endocrinological disturbances model); (2) meniscectomy (mechanical stress model); and (3) immobilization of the hind leg (nutritional disorder model). After 12 weeks of methylprednisolone (MP) administration, the rabbit femur heads displayed cartilage erosions, marked decrease of glycosaminoglycans (GAG) content, and narrowing of joint spaces. Elevation of serum uronic acid, activity of alkaline phosphatase, and calmodulin content was evident. All these changes were minimal--close to normal--in the group treated for 12 weeks with MP + salmon calcitonin (sCT). Partial meniscectomy and hind leg immobilization caused statistically significant loss of GAG from the cartilage and narrowing of the knee joint space during the same experimental period, 12 weeks. In both these models the groups of rabbits treated simultaneously with sCT showed only insignificantly smaller joint spaces and GAG content. These results support our hypothesis of a chondroprotective property of calcitonin. However, the mechanism through which calcitonin influences joint cartilage remains unknown. A direct effect of calcitonin on cultivated chondrocytes, as well as the role of calmodulin, beta-endorphins, calcium, and interleukin-1 in the process are discussed.
...
PMID:Chondroprotective action of salmon calcitonin in experimental arthropathies. 189 93

Effects of chlorpromazine on the mineralization and alkaline phosphatase activity (ALP) in the tooth germ were examined and compared with those of retinoic acid and HEBP (1-hydroxyethylidene-1, 1-bisphosphonate). Mandibular first molars from 17-day-old mouse embryos were cultured with or without drugs. Calcium content and ALP in the tooth germ increased gradually from 0 to 7 days in culture, the increase of calcium being preceded by that of ALP. Retinoic acid suppressed increases of calcium and ALP in the tooth germ but not in the specimens precultured for 2 days, suggesting that retinoic acid inhibits the mineralization at an early developmental stage of the tooth. HEBP, a physiochemical inhibitor of mineralization, suppressed the increase of calcium, but significantly enhanced the increased of ALP in the tooth germ. Chlorpromazine, which has an antagonistic action towards calmodulin, also suppressed the increases of calcium and ALP in the tooth germ. Calmodulin antagonists W-7 and W-5 similarly suppressed the increases of calcium and ALP; W-5 had less effects on both calcium and ALP. These results indicate that calmodulin may be involved in the regulation of the mineralization in the tooth germ. These drugs are shown to possess different modes of inhibitory action on the mineralization.
...
PMID:[In vitro effect of chlorpromazine on the mineralization of tooth germ in mice--comparison with that of retinoic acid and HEBP]. 190 64

1. Current mediated by GABAA receptors was examined in pyramidal cells acutely dissociated from the hippocampus of mature guinea-pigs. Current responses were measured using whole-cell voltage-clamp recordings. An internal perfusion technique was used to change the intracellular contents during recording. 2. Application of GABA (100-300 microM) by short duration pressure pulses produced outward current responses at a holding potential of -10 mV. When recordings were made with intracellular solutions which did not contain Mg-ATP, GABA responses progressively decreased to less than 10% of their initial values after 10 min. This 'run-down' of the GABA response could not be accounted for by desensitization since the rate of run-down was not dependent upon agonist application. 3. The run-down of the GABAA response was reversed when Mg2+ (4 mM) and ATP (2 mM) were introduced into the intracellular perfusate. In addition to the presence of Mg-ATP, buffering of Ca2+ in the intracellular solution to low levels (approximately 10(-8) M) was also necessary to stabilize the GABAA response. 4. The role of a phosphorylation process in regulating the GABAA receptor was tested. After the GABA response stabilized, introduction of alkaline phosphatase (100 micrograms/ml) to the intracellular perfusate caused a complete run-down of the GABA response. 5. Stable GABA responses were obtained when ATP was replaced by ATP-gamma-S (adenosine 5'-O-(thiotriphosphate), an analogue of ATP that donates a thiophosphate group resulting in a product that is more resistant to hydrolysis. Following such treatment GABA responses declined more slowly after the introduction of intracellular alkaline phosphatase. 6. Run-down of GABA responses accelerated when intracellular Ca2+ concentration ([Ca2+]i) was elevated to about 5 x 10(-4) M. The run-down caused by elevated [Ca2+]i could be stopped and reversed by reducing [Ca2+]i to about 10(-8) M. 7. The introduction of ATP-gamma-S to the intracellular medium retarded the run-down of GABA responses caused by elevation of [Ca2+]i. 8. N-(6-Aminohexyl)-5-chloro-1-naphthalenesulphonamide (W-7), a calmodulin inhibitor, reduced the rate of run-down induced by elevated [Ca2+]i. 9. These results suggest that the function of the GABAA receptor is maintained by phosphorylation of the receptor or some closely associated regulatory molecule. Elevation of [Ca2+]i destabilizes the function of the GABAA receptor, probably by activating a Ca2+/calmodulin-dependent phosphatase.
...
PMID:GABAA receptor function is regulated by phosphorylation in acutely dissociated guinea-pig hippocampal neurones. 215 38

A specific soluble inositol phosphate 5-phosphomonoesterase has been purified approximately 2,700-fold from a 120,000g supernatant of rabbit neutrophil homogenate. The specific enzyme represented 25-50% of the total hydrolytic activity toward inositol, 1,4,5-trisphosphate (Ins-1,4,5-P3) with the remaining activity hydrolyzing both Ins-1,4,5-P3 as well as inositol 1,4-bisphosphate (Ins-1,4-P2). However, the enzyme could not be identified on sodium dodecyl sulfate-polyacrylamide gels stained with Coomassie blue, indicating that it represents a minor protein in the purified enzyme preparations. The purified enzyme has an apparent molecular mass of 43,000-47,000 daltons as determined by gel filtration and is free of other inositol phosphate phosphomonoesterases. The enzyme hydrolyzes Ins-1,4,5-P3 with an apparent Km of 18 microM and a Vmax of 1.2 mumol/min/mg. The 5-phosphomonoesterase requires Mg2+ for activity and is not affected by physiological concentrations of Ca2+ or calmodulin. The pH optimum for activity is 7.5. Inositol 1,3,4,5-tetrakisphosphate is a potent competitive inhibitor of Ins-1,4,5-P3 hydrolysis (Ki = microM), whereas Ins-1,4-P2 is a weak inhibitor (Ki = 173 microM). Ins-1,4,5-P3 hydrolysis is relatively unaffected by monophosphorylated substrates, however, bisphosphorylated substrates are potent inhibitors. Comparisons of neutrophil 5-phosphomonoesterase characteristics with those of platelet and rat brain enzymes support the idea that each 5-phosphomonoesterase may be a unique enzyme and play a different role dependent upon the cell or tissue in which it acts.
...
PMID:Purification and characterization of soluble inositol 1,4,5-trisphosphate 5-phosphomonoesterase from rabbit peritoneal neutrophils. 216 94

The pregnenolone-binding protein (PBP) in guinea pig adrenocortical cytosol is inactivated (converted to a nonsteroid-binding form) by incubation with calf intestinal alkaline phosphatase at pH 9. Previously bound pregnenolone does not prevent this inactivation, and dephosphorylation causes dissociation of bound ligand from the protein. Cytosolic PBP, partially purified PBP, and highly purified PBP are equally susceptible to alkaline phosphatase-mediated inactivation. No change in apparent molecular weight or immunoreactivity is evident by Western blot analysis. Loss of pregnenolone-binding capacity of cytosolic PBP (but not partially purified PBP) could be reversed by inhibiting the phosphatase, lowering the pH to approximately 7, and adding ATP to the incubation. Reactivation is absolutely and specifically dependent upon ATP, which restores binding capacity in a concentration-dependent manner. Other nucleoside triphosphates, including the nonhydrolyzable ATP analogue adenosine 5'-(beta, gamma-imido)triphosphate, as well as cAMP and cGMP are ineffectual as cofactors for reactivation. These data strongly implicate a cytosolic kinase which is apparently inactivated or separated from PBP during purification. Preliminary investigations indicate that the reactivating kinase is not cAMP-dependent, but may have a requirement for calcium and/or calmodulin. The identification of phosphorylation/dephosphorylation as the regulatory mechanism for steroid binding should prove pivital in elucidating the functional role of PBP.
...
PMID:Regulation of adrenocortical pregnenolone-binding protein activity by phosphorylation/dephosphorylation. Phosphatase-mediated inactivation is reversed by cytosolic kinase. 216 58

Highly purified growth hormone (GH) has been isolated from Atlantic salmon (Salmo salar) pituitaries by extraction with acid acetone, acidic precipitation, and reversed-phase high-performance liquid chromatography (HPLC). The yield was 2.5 mg/g wet tissue. The Atlantic salmon GH (sGH) emerged as a single symmetrical peak after HPLC on a reverse phase C18 column. SDS-gel electrophoresis revealed only one band with an estimated molecular weight of 23,000. Atlantic sGH showed a uniform molecular weight, but two-dimensional (2D) gel electrophoresis of the purified sGH revealed charge heterogeneity with pI's ranging from 6.5 to 8.2. Treatment of the purified sGH with alkaline phosphatase concentrated these different forms into a single more alkaline position (pI 8.2) indicating removal of acidic groups. These results were documented using both silver- and immunostaining of the 2D SDS gels. The purified sGH was phosphorylated in vitro by a calmodulin-dependent protein kinase. Phosphorylation of sGH may be a post-translational modification resulting in several molecular forms with variable acidity. Analysis of the amino acid composition of Atlantic sGH revealed homology with GHs isolated from other teleost species and the amino-terminal sequence showed only three different amino acids within the first 25 residues compared to GH isolated from chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch) pituitaries. Atlantic sGH had a methionine as the amino-terminal residue. Antibodies against chum sGH cross-reacted with Atlantic sGH. Antibodies against either Atlantic or chinook (Oncorhynchus tschawytscha) salmon prolactin or human GH did not cross-react with Atlantic sGH. Atlantic sGH was shown to have a slight growth-promoting activity in the rat tibia assay.
...
PMID:Purification and characterization of Atlantic salmon growth hormone and evidence for charge heterogeneity. 228 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---