Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00631 (Gel)
 14,881 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A technique for the demonstration of a human steroid and organ-specific prostate cytosol receptor is described. Tissue from 17 patients with benign prostatic hypertrophy was incubated in Eagle's medium with 3H-testosterone (T) .06 nM following pre-incubation with an anti-androgen. The minces were homogenized and the cytosol fraction obtained. The cytosol was then fractionated on a duo-gel column of G-50 Sephadex over Bio-gel A 1.5m and fractions counted for 3H, assayed for protein and plotted graphically. Three main peaks were seen. Only the second peak (approximately 150,000 mol wt), which contained predominantly dihydrotestosterone (DHT), was significantly and reproducibly inhibited by 2.1 muM cyproterone acetate (Cyp A) pre-incubation. This inhibiton was considered a specific indicator for receptor since Cyp A at muM had little effect (less than 10%) on 3H-DHT binding to plasma. Similar results were noted for other anti-androgens tested, but cortisol and etiocholanolone had no effects on 3H-5alpha DHT binding to prostate cytosol. Steroid-protein peaks for fractionated human thyroid, muscle, and spleen cytosol were not inhibited by Cyp A. Fractionated kidney cytosol contained a 3H-T-binding protein peak which was significantly decreased by Cyp A. Pronase incubation and heating at 50 C for 30 min both resulted in either a significant decrease or complete loss of receptor. Gel filtration analysis of 3H-cytosol derived from human prostate minces pre-incubated with and without Cyp A, provides a relatively rapid technique for the demonstration of cytosol receptor in approximately 80% of prostates from patients with benign prostatic hypertrophy.
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PMID:Evidence for a specific dihydrotestosterone-binding cytosol receptor in the human prostate. 5 54

To determine the length of secreted nascent polypeptide chain that is surrounded by membrane, we digested labeled nascent chains protruding from protoplasts of Bacillus subtilis with Pronase and isolated the residual ribosome-attached chains from the membrane-polysome fraction. Gel chromatography revealed a sharp major peak that had been protected by membrane plus bound ribosomes. The ribosomes themselves protected half as great a length. Because no free chain between the ribosome and the membrane was detected by Pronase treatment, the difference between the two protected lengths should measure the length protected by the membrane. More accurate measurements of these lengths, obtained by dansylation of the exposed NH2 terminus of the isolated fragments, yielded a difference of 21 amino acids. This value corresponds to an extended chain of 75 A, which is approximately the thickness of the bacterial cell membrane. We earlier presented evidence that bacterial ribosomes are attached to membrane solely by their secreted chain. The present results further show that after loss of the extracellular segment of the chain its attachment persists, at 37 degrees as well as 0 degrees C. These findings suggest that the chain does not slip through a passive membrane but is actively held within a channel.
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PMID:Interaction of secreted nascent chains with surrounding membrane in Bacillus subtilis. 10 95

Chicken embryo fibroblasts (C/E phenotype) infected with subgroups B and C of the Prague strain of Rous sarcoma virus were radiolabeled with either [6-(3)H]-glucosamine or [2-(3)H]mannose, and virus was purified from the growth medium. The large envelope glycoprotein, gp85, was the only major radiolabeled component of purified virus. Pronase-digested glycopeptides from purified virus were analyzed by a combination of (i) gel filtration with columns of Sephadex G15/G50 and Bio-Gel P4 and (ii) enzymatic digestion of the oligosaccharide chains with specific exoglycosidases and endo-beta-N-acetylglucosaminidases. The rather broad molecular weight distribution (approximately 2,000 to 4,000) for glycopeptides in these studies and previous studies in other laboratories was shown to represent actual heterogeneity in the carbohydrate moieties: (i) the glycopeptides contained both mannose-rich, neutral chains and complex, acidic chains with terminal sialic acid; and (ii) both classes of asparagine-linked carbohydrate structures exhibited heterogeneity in the size of the oligomannosyl core (a mixture of approximately 5 to 9 mannose units for the neutral structures, and 3 or 5 mannose units for the acidic structures). With the [2-(3)H]mannose-labeled glycopeptides from Rous sarcoma virus, Prague strain subgroup C, most of the oligosaccharide chains were high-molecular-weight, acidic structures, with similar numbers of 3-mannose and 5-mannose core structures.
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PMID:Oligosaccharide chains of avian RNA tumor virus glycoproteins contain heterogeneous oligomannosyl cores. 21 28

The carbohydrate composition and oligosaccharide structure of three glycopeptides isolated from delipidated calf thymocyte plasma membranes following Pronase digestion have been determined. Five major glycopeptide fractions were separated using Bio-Gel P-6 gel filtration and diethylaminoethylcellulose chromatography. The structure of the oligosaccharide chains of three of these glycopeptides was determined by a combination of sequential degradation with glycosidases and methylation analysis. These oligosaccharide structures consist of complex, highly branched N-linked chains containing at their nonreducing termini the unusual sequence Gal(beta1 leads to 3)Gal(beta1 leads to 4)GlcNAc leads to as well as the more usual sequence SA(alpha2 leads to 3)Gal(beta1 leads to 4)GlcNAc leads to. In addition, one glycopeptide also contains short O-linked chains with the structure Gal(beta leads to 3)GalNAc leads to Ser(Thr) which have receptor activity for the lectin from the mushroom Agaricus bisporus.
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PMID:Structure of the oligosaccharides of three glycopeptides from calf thymocyte plasma membranes. 30 61

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

Rats (14 days old) were injected with [14c]fucose and young adult rats with [3H]fucose in order to label the myelin-associated glycoproteins. As previously reported, the major [14C]fucose-labelled glycoprotein in the immature myelin had a higher apparent molecular weight on sodium dodecyl sulphate/polyacrylamide gels that the [3H]fucose-labelled glycoprotein in mature myelin. This predominant doubly labelled glycoprotein component was partially purified by preparative gel electrophoresis and converted to glycopeptides by extensive Pronase digestion. Gel filtration on Sephadex G-50 separated the glycopeptides into several clases, which were designted A,B, C AND D, from high to low molecular weight. The 14C-labelled glycopeptides from immature myeline were enriched in the highest-molecular-weight class A relative to the 3H-labelled glycopeptides from mature myelin. Neuraminidase treatment of the glycoprotein before Pronase digestion greatly decreased the proportion of glycopeptides fractionating in the higher-molecular-weight classes and largely eliminated the developmental differences that were apparent by gel filtration. However, neuraminidase treatment did not decrease the magnitude of the developmental difference revealed by electrophoresing the intact glycoprotein on sodium dodecyl sulphate gels, although it did decrease the apparent molecular weight of the glycoprotein from both the 15-day-old and adult rats by an amount comparable in magnitude to that developmental difference. The results from gel filtration of glycopeptides indicate that there is a higher content of large molecular weight, sialic acid-rich oligosaccharide units in the glycoprotein of immature myelin. However, the higher apparent molecular weight for the glycoprotein from 15-day-old rats on sodium dodcyl sulphate gels is not due primarily to its higher sialic acid content.
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PMID:Effects of pronase and neuraminidase treatment on a myelin-associated glycoprotein in developing brain. 94 96

Cells of corticoid-sensitive (CS) and corticoid-resistant (CR) lymphosarcoma P1798 were labeled in vivo with either [14C]- or [3H]fucose before and after treatment with 9-alpha-fluoroprednisolone (9-FP). Labeled glycopeptides, derived from isolated, Pronase-digested cell membranes of both tumors were separated by gel filtration on Bio-Gel P-10 by a double-label technique. Elution profiles of CS and CR fractions showed significant differences in early eluting material. Desialylation of glycopeptides by neuraminidase lowered the molecular weight of both CS and CR fractions, and altered 3H:14C ratios indicated that CS and CR sialoglycopeptides are different. 9-FP treatment for 7 hr increased the density of isolated P1798-CS and -CR cell membranes. All CS and CR glycopeptides from treated tumors eluted faster than did those of untreated preparations. Both CS and CR sialoglycopeptides were altered, although differences in CS and CR profiles persisted. Histochemical investigations indicated that negative charge, present on surfaces of untreated CS cells, is lost between 6 and 8 hr after exposure in vivo to 9-FP. CR cells had no or few anionic sites on their surfaces before and after steroid administration. We demonstrated that glycopeptides of both CS and CR tumors contain sialic acid, although only CS cells carry a surface-exposed negative charge that is lost after 9-FP treatment. Glucocorticoids alter both P1798-CS and -CR sialoglycopeptides, but the consistent differences between their chromatographic patterns suggest that steroid-induced changes in cell membranes of the two tumors are not identical. Cell death or survival of glucocorticoid-treated P1798 cells may, therefore, be influenced by specific structural characteristics involving cell surface sialoglycoproteins.
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PMID:Cell membrane sialoglycopeptides of corticoid-sensitive and -resistant lymphosarcoma P1798. 94 64

Semliki Forest virus was grown in BHK cells and labeled in vivo with radioactive monosaccharides. Pronase digests of the virus chromatographed on Bio-Gel P6 revealed glycopeptides of A-type and B-type. (For the nomenclature see Johnson, J. and Clamp, J.R. (1971) Biochem. J. 123, 739-745.) The former was labeled with [3H]fucose, [3H]galactose, [3H]mannose and [14C]glucosamine, the latter only with [3H]mannose and [14C]glucosamine. The three envelope glycoproteins E1, E2 and E3 were isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to pronase digestion. The glycoproteins E1 and E3 revealed glycopeptides of A-type. E2 revealed glycopeptides of B-type. E2 yielded additionally a glycopeptide (Mr3100) which was heavily labeled from [3H]galactose, but only marginally from [14C]glucosamine, [3H]fucose and [3H]mannose. Whether this glycopeptide belongs to the A-type or not remains uncertain. The apparent molecular weights of the A-type units measured by gel filtration were 3400 in E1 and 4000 in E3; the B-type unit of E2 had an apparent molecular weight of 2000. Combined with the findings of our earlier chemical analysis these data suggest that E1 and E3 contain on the average one A-type unit; E2 probably contains one 3100 dalton unit plus one or two B-type units.
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PMID:Protein-bound oligosaccharides of Semliki Forest virus. 124 69

A major glycoprotein 36 000 molecular weight) has been isolated from lung lavage of patients with alveolar proteinosis and found to contain five residues of hydroxyproline, fifty residues of glycine, three residues of methionine, 3 mol of sialic acid, 4.4 mol of mannose, 4.0 mol of galactose, 6.0 mol of glucosamine, and 1 mol of fucose. Cyanogen bromide (CNBr) treatment of the glycoprotein resulted, as expected, in four peptides of apparent molecular weights of 18 000, 12 000, 5000 and 1000, respectively. The chemical compositions of the CNBr peptides indicate the presence of hydroxyproline and high amounts of glycine in all but one of the peptides; two of the four CNBr peptides contain carbohydrate. Gel filtration, acrylamide gel electrophoresis and end-group analyses of the native glycoprotein and its CNBr peptides indicate that the peptides are homogeneous. End-group analyses of the CNBr cleavage products assign the 18 000 molecular weight peptide to the NH2-terminal portion and the 1000 molecular weight peptide to the COOH-terminal portion of the native glycoprotein molecule. Pronase digestion of the 36 000 molecular weight glycoprotein, followed by gel filtration and cation exchange chromatography, resulted in two fractions. One fraction was acidic and contained all the carbohydrate, a high content of aspartic acid and no hydroxyproline. The other fraction was basic and contained 8.4% hydroxyproline, 14% proline, 28% glycine and no carbohydrate, suggesting the presence of collagen-like sequence in the peptide chain. Paper electrophoresis of the basic fraction demonstrated two components, the amino acid compositions of which are identical to those of collagen. Partial amino-terminal sequence analysis of one of the CNBr peptides (18 000 molecular weight) indicated the presence of -Fly-Pro-HyP-Gly-sequence in the peptide chain, which confirms our suggestion that collagen-like regions are present in the native glycoprotein molecule. Limited acid hydrolysis of the acidic fraction and subsequent fractionation of the acid hydrolysate using Dowex column yielded a fraction which produced brown colour with ninhydrin reagent. Paper chromatography of this fraction demonstrated a large component which also stained brown with ninhydrin reagent. After acid hydrolysis, this component was found to consist of equal amounts of asparitic acid and glucosamine, indicating that the N-acetylglucosamine of the oligosaccharides is linked to the asparagine residue of the peptide. No serine or threonine linkages are present.
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PMID:Structural studies on a glycoprotein isolated from alveoli of patients with alveolar proteinosis. 126 11

Poly-N-acetyllactosamine extension has been found in O-glycans in addition to N-glycans and glycosphingolipids. Attempts were made in HL-60 and K562 cells to determine the amount of poly-N-acetyllactosaminyl O-glycans in the major sialoglycoprotein, leukosialin. Leukosialin was immunoprecipitated from [3H]glucosamine-labeled HL-60 and K562 cells. Glycopeptides were prepared by Pronase digestion, and O-glycan-containing glycopeptides were isolated by affinity chromatography using Jacalin-agarose. The glycopeptides bound to Jacalin-agarose and those unbound were treated with alkaline borohydride, and the released O-glycans were fractionated by Bio-Gel P-4 filtration. Sequential glycosidase digestion of the O-glycans, with or without pretreatment by fucosidase or neuraminidase, revealed the following conclusions. 1) Leukosialin from HL-60 cells contains about 1-2 poly-N-acetyllactosaminyl O-glycan chains/molecule. 2) About 50% of these poly-N-acetyllactosaminyl O-glycans contain sialyl Le(x) termini, NeuNAc alpha 2-->3Gal beta 1-->4 (Fuc alpha 1-->3)GlcNAc beta 1-->R. The amount of sialyl Le(x) structure in leukosialin is roughly equivalent to that on cell surfaces of HL-60 cells. 3) Leukosialin from K562 cells, on the other hand, contains no detectable amount of poly-N-acetyllactosaminyl O-glycans. 4) The presence of poly-N-acetyllactosamine in O-glycans is dependent on the core 2 beta 1,6-N-acetylglucosaminyl transferase. 5) Jacalin-agarose binds to sialylated small oligosaccharides such as NeuNAc alpha 2-->3Gal beta 1-->3(NeuNAc alpha 2-->6) GalNAc but not the hexasaccharide NeuNAc alpha 2-->3Gal beta 1-->3(NeuNAc alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->6) GalNAc. These results indicate that the formation of polylactosaminyl O-glycans and sialyl Le(x) structure in O-glycans is dependent on the core 2 formation.
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PMID:Poly-N-acetyllactosaminyl O-glycans attached to leukosialin. The presence of sialyl Le(x) structures in O-glycans. 144 88


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