Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acid phosphatase activity in homogenized tibiae and femora of suckling rats was extracted with 0.3M KCl and 0.1% Triton X-100. A high-speed supernatant was treated with protamine sulfate, dialyzed, and chromatographed on CM-52 cellulose. All of the acid phosphatase activity was eluted with a sodium acetate buffer and combined ionic strength-pH gradient into two peaks (E1 and E2). Both enzyme peaks were further purified with Sephadex G-200, which resulted in 700- and 1000-fold purification for E2 and E1, respectively. A total of 220 units (mumoles substrate/min) of E2 with a specific activity of 160 units/mg protein has been obtained in one run by this procedure. E1 has a high molecular weight (greater than 100,000) and shows preference for monophosphate ester substrates, is markedly inhibited by tartrate, and has a pH optimum near 5. E2 has a lower molecular weight (greater than 40,000) and shows negligible activity with monophosphate esters [except with p-nitrophenyl phosphate (p-NPP)], but high activity with ADP and ATP. E2 is unaffected by tartrate and shows a pH optimum near 6. Both enzymes are competitively inhibited by inorganic phosphate, and E2, but not E1, is markedly inhibited by p-chloromercuribenzoate. With p-NPP as substrate, E1 and E2 have distinctly different values for Km. E1 appears similar to the high molecular weight acid phosphatases of soft tissues. However, E2 appears to differ from the low molecular weight phosphatases in soft tissues with regard to substrate specificity.
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PMID:Purification and partial characterization of two acid phosphatases from rat bone. 11 82

Extracts of tibiae of suckling rats were prepared with 0.3 M KCl containing 0.1% Triton X-100 and were chromatographed with CM-52 cellulose. Most of the acid phosphatase activity determined with p-nitrophenylphosphate (p-NPP) was bound to the cellulose and could be eluted with a sodium acetate buffer gradient in 2 distinct peaks. The major peak, E2, was bound strongly to the cellulose and showed high activity with p-NPP and inorganic pyrophosphate (P-Pi), but only slight activity with beta-glycerophosphate (beta-GP) and was unaffected by tartrate. The minor peak, E1, was weakly bound to the adsorbent, showed equal activity with p-NPP and beta-GP, but negligible activity with P-Pi and was completely inhibited by tartrate. These results support earlier evidence suggesting that bone contains at least 2 different acid phosphatases and that the more abundant enzyme may function as a pyrophosphatase.
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PMID:Chromatographic separation of two acid phosphatases from rat bone. 20 77

The alpha-melanocyte-stimulating hormone (alpha-MSH) receptor of B16 mouse melanoma cells was characterized by photoaffinity labelling using radiolabelled photoactive derivatives of alpha-MSH. A doublet band of 43-46 kDa representing a ligand-receptor complex was identified. A novel adaptation of the streptovadin/biotin-based affinity system was used to isolate the alpha-MSH receptor. A probe was synthesized which contained biotin connected to a photolabelled alpha-MSH analogue via a cleavable disulphide linker and which displayed high affinity for the alpha-MSH receptor. Streptavidin-coated magnetic beads were used as a solid support instead of an affinity column. Covalently linked probe-receptor complexes solubilized in Triton X-100 were equilibrated with the beads, and after magnetic separation and washing, specifically bound complexes were treated with dithiothreitol to cleave the disulphide bridge in the biotin-peptide spacer arm and so release the receptor-ligand complex. The identity of the isolated protein was established by SDS/PAGE analysis. Methods to achieve purification to homogeneity and to allow quantitative isolation of the receptor are discussed.
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PMID:Isolation and partial purification of a melanocyte-stimulating hormone receptor from B16 murine melanoma cells. A novel approach using a cleavable biotinylated photoactivated ligand and streptavidin-coated magnetic beads. 132 40

The association of endogenous synenkephalin and met-enkephalin containing peptides with the membrane of bovine chromaffin granules and physicochemical characteristics of this association were studied. The associated materials were only released at a non physiological pH range and this effect was enhanced with growing salt concentrations (0.5, 1.0 and 2.0 M KSCN). A higher peptide dissociation occurred with membrane solubilizing agents (SDS greater than Triton X-100 greater than digitonin). In microsomes the materials dissociated with 2 M KSCN (pH 7.4) corresponded to peptides larger than 12.0 kDa, while in granules corresponded to molecules smaller than 8.5 kDa, displaying synenkephalin and met-enkephalin immunoreactivities. These data suggest that some sequence of the C-terminal portion of synenkephalin may be responsible for the association of proenkephalin derived peptides with microsome and granule membranes.
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PMID:Association of endogenous synenkephalin containing peptides with intracellular membranes of bovine adrenal medulla. 292 40

Incubation of rat adipocytes with the same range of noradrenaline concentrations that stimulate lipolysis caused a rapid and stable decrease in the activity of fatty acyl-CoA synthetase. Corticotropin, glucagon and dibutyryl cyclic AMP also decreased the activity of the enzyme. The effect of noradrenaline was apparent over a wide range of concentrations for the three substrates of the enzyme. A novel fluorescence assay of fatty acyl-CoA synthetase using (1,N6-etheno)-CoA is described. The effect of noradrenaline was not abolished by inclusion of albumin in homogenization buffers, persisted through subcellular fractionation and isolation of microsomes (microsomal fractions) and even survived treatment of microsomes with Triton X-100. The effect of noradrenaline was rapidly reversed within cells by the subsequent addition of insulin or propranolol. The inclusion of fluoride in homogenization buffers did not alter the observed effect of noradrenaline. Additions of cyclic AMP-dependent protein kinase to adipocyte microsomes caused considerable phosphorylation of microsomal protein by [gamma-32P]ATP, but did not affect the activity of fatty acyl-CoA synthetase.
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PMID:Reversible inactivation by noradrenaline of long-chain fatty acyl-CoA synthetase in rat adipocytes. 388 97

The presence of a high-molecular weight complex with acid phosphatase activity in the cytosol of human mammary tumors is reported. This complex appeared in the cytosol after tissue homogenization in the presence of dithiotreitol, with or without Triton X-100 and at acidic or neutral pH. Upon gel electrophoresis, this fraction showed only one band of enzyme activity which did not enter the fine pore gel. Lubrol or n-butanol had no apparent effect on this complex, and 8 M urea or 2% sodium dodecyl sulfate did not disaggregate this large molecule. After purification by gel filtration, ammonium sulfate precipitation and ion-exchange chromatography an apparent molecular weight or 10(6) was measured. It hydrolyzed typical acid phosphatase substrates such as p-NPP and alpha-NP, but also ATP and PPi. Only 44% inhibition was observed with L-(+)tartrate and it was still 40% active after 1 hr incubation at 60 degrees C. Reduction in the presence of SDS yielded several polypeptide bands. It was also detected in some samples of normal mammary tissues, but not in normal human placenta or liver.
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PMID:A high-molecular weight complex with acid phosphatase activity in human breast cancer. 609 19

Surfactants, a group of nonspecific membrane perturbating substances, can cause nerve damage. Various concentrations of the cationic surfactants benzalkonium chloride (BAC) and benzethonium chloride, the anionic surfactants sodium ricinoleate, dioctyl sodium sulfosuccinate and sodium lauryl sulfate and the nonionic surfactant Triton X-100 were applied to the serosal surface of the rat jejunum every 5 min for 0.5 hr and then rinsed off with saline. Thirty days after surfactant application, the treated and an untreated segment of jejunum were removed and examined histologically. All surfactants which were tested significantly reduced the number of ganglion cells in the myenteric plexus. In addition, sodium ricinoleate significantly reduced the number of ganglion cells in the submucosal plexus. Higher concentrations of the cationic agents BAC and benzethonium chloride caused a generalized tissue damage including disruption of the smooth muscle, lymphocytic infiltration, intestinal perforation and death. Using BAC as a prototype surfactant, peptidergic neuron distribution and gut electrical activity were examined. BAC treatment markedly reduced the immunoreactivity of somatostatin, substance P, met-enkephalin and vasoactive intestinal peptide in the myenteric plexus. In addition, the electric properties of the smooth muscle were altered. BAC treatment resulted in an erratic, markedly distorted basic electric rhythm and an alteration in spike potential generation. These studies demonstrate that surfactants in appropriate concentrations selectively ablate the myenteric neurons and alter peptidergic neuron distribution and gut electrical parameters in the rat jejunum.
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PMID:Surfactants selectively ablate enteric neurons of the rat jejunum. 619 30

Rat bone was extracted with KCl and Triton X-100, and a tartrate-resistant acid phosphatase activity was purified by protamine sulfate precipitation, ion-exchange chromatography (CM-cellulose), and gel filtration on Sephadex G-200 according to previously described procedures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining demonstrated a major band with an apparent monomer molecular size of approximately 14,000 Da. The enzyme is active with p-nitrophenylphosphate (p-NPP) but exhibits a 5- to 10-fold higher affinity towards several nucleotides of which ATP and ADP are the most readily hydrolyzed substrates based on kinetic studies. Based on sensitivity towards proteolytic treatment and detergent removal, as well as pH-optimum studies, a single enzyme was found to be responsible for activity towards nucleotide phosphates as well as p-NPP. This nucleotide tri- and diphosphatase constitutes around 15% of the total acid phosphatase activity in rat bone. The activity with ATP as substrate in contrast to that with p-NPP was inhibited in a noncompetitive fashion by MgCl2, sodium metavanadate, and p-chloromercuribenzoate. Enzyme activity with p-NPP and ATP is dependent on the presence of KCl and detergent and is activated by Fe3+ and ascorbate. The reported characteristics of the enzyme suggest that it functions as a unique membrane acid ATPase.
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PMID:Purification and characterization of a vanadate-sensitive nucleotide tri- and diphosphatase with acid pH optimum from rat bone. 623 50

A macromolecular aggregate of corticotropin-beta-lipotropin common precursor had been observed in ovine pituitary preparations as an excluded fraction of Sephadex G-200 gel filtration. This fraction could not penetrate a 10% gel during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, when 2-mercaptoethanol or other disulfide-cleaving agents were not present in the buffer used to solubilize the protein preparation prior to the electrophoresis. On a 4.6% gel (acrylamide:bisacrylamide, 20:1), the material migrated as a diffuse band to a position between those of beta-galactosidase (Mr 130 000) and myosin (Mr 200 000). Both observations were consistent with an apparent Mr greatly in excess of that of the corticotropin-beta-lipotropin common precursor reported by many investigators. Neither 5% SDS nor 1% Triton X-100 could dissociate the macromolecular aggregate, but 2-mercaptoethanol and urea, either alone or in combination, were able to dissociate it to two main protein components, one of which was identified as corticotropin-beta-lipotropin with an apparent Mr of 34 000. The fact that urea alone could dissociate this macromolecular aggregate led us to believe that it might be a non-covalent aggregate and that 2-mercaptoethanol probably did not achieve the dissociation through the cleavage of an interchain disulfide bond but by bringing about conformational changes as a result of reduction of intrachain disulfide bonds so that aggregation became unfavorable. Moreover, the dissociation by urea or by 2-mercaptoethanol was found to be irreversible. The origin of the macromolecular aggregate of corticotropin-beta-lipotropin common precursor remains obscure.
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PMID:Characterization of a macromolecular aggregate of ovine pituitary corticotropin-beta-lipotropin common precursor. 626 48

During development of the calcitonin binding assay using rat brain particulate fraction, it was noticed that 125l-salmon calcitonin-l (125-SCT) was partly absorbed by the polypropylene tube surface in an irreversible manner. Absorption was partially prevented by cold SCT and complete prevention was achieved by bacitracin. Triton X-100, Brij 36T, and some Zwittergents in such concentration ranges which appeared not to disrupt the 125l-SCT binding ability of brain tissue. The brain fraction itself exhibited a similar preventive effect. The anti-absorbing effect of Brij 36T was also observed in an opiate receptor binding assay for beta-endorphin. These results led us to recommend that the binding assay for these peptides should be done only in the presence of an appropriate anti-absorbant.
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PMID:Absorption loss of peptides to the plastic tube in radioreceptor assay of calcitonin and beta-endorphin: protection by detergents. 628 68


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