scholarly journals Chemical cross-linking of chick oviduct progesterone-receptor subunits by using a reversible bifunctional cross-linking agent

1979 ◽  
Vol 181 (1) ◽  
pp. 201-213 ◽  
Author(s):  
M E Birnbaumer ◽  
W T Schrader ◽  
B W O'Malley
Keyword(s):  
Progesterone Receptor ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Sedimentation Coefficient ◽  
Sucrose Density Gradient ◽  
Cross Linking ◽  
Sucrose Density Gradient Centrifugation ◽  
Receptor Proteins ◽  
The Cross

Chick oviduct progesterone-receptor proteins were treated in cytosol with the reversible cross-linking reagent methyl 4-mercaptobutyrimidate. The product of the reaction was a 7S complex that could be detected and recovered after sucrose-density-gradient centrifugation in 0.3M-KCl. The extent of the reaction was dependent on the concentration of methyl 4-mercaptobutyrimidate and independent of the presence of bound hormone, since unlabelled receptors could also be cross-linked. The cross-linking reaction required conditions in which the cytosol 6S complex was preserved. A Stokes radius of 7.3 nm was determined by gel filtration in Agarose A-1.5 m in 0.3 M-KCl. The sedimentation coefficient, which was also determined in 0.3 M-KCl, allowed us to calculate a mol. wt. of 228,000. We were also able to cross-link partially purified receptor forms isolated by using an Agarose A-15 m column. On reduction with beta-mercaptoethanol the complex broke down to 4S monomers that were identified by DEAE-cellulose and phosphocellulose chromatography, adsorption on DNA-cellulose and gel filtration in an Agarose A-1.5 m column. In most cases, A and B receptor proteins were released in equivalent amounts, implying that the cross-linked form was an A-B complex.

Molecular characteristics of cytostatic factors in amphibian egg cytosols

Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 799-808
Author(s):  
E.K. Shibuya ◽  
Y. Masui
Keyword(s):  
Density Gradient ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Sucrose Density Gradient ◽  
Molecular Characteristics ◽  
Small Peptides ◽  
Sucrose Density Gradient Centrifugation ◽  
Cytostatic Factor

In amphibians, zygotes microinjected with cytosol of unactivated eggs are arrested at metaphase of mitosis. The factor responsible for this effect has been designated ‘cytostatic factor, (CSF)’. CSF is inactivated by Ca2+ addition to cytosols. During storage of the Ca(2+)-containing cytosols, a stable CSF activity develops. Therefore, the first Ca(2+)-sensitive CSF and the second Ca(2+)-insensitive CSF have been referred to as primary CSF (CSF-1) and secondary CSF (CSF-2), respectively. We have partially purified CSF-1, which had been stabilized with NaF and ATP, and CSF-2 from cytosols of Rana pipiens eggs by ammonium sulphate (AmS) precipitation and sucrose density gradient centrifugation or gel filtration, and investigated their molecular characteristics. CSF-1 was sensitive to protease, but resistant to RNAse, and inactivated within 2 h at 25 degrees C. CSF-1 could be sedimented in a sucrose density gradient from a fresh cytosol or its crude fraction precipitated at 20–30% saturation of AmS, showing the sedimentation coefficient 3S. When analyzed by SDS-polyacrylamide gel electrophoresis (PAGE), all the proteins in partially purified CSF-1 samples entered the gel and were separated into numerous peptide bands. In contrast, CSF-2 was an extremely large molecule, being eluted from Sepharose columns as molecules larger than 2 × 10(6), and failed to enter the gel when analyzed by SDS-PAGE. It could be purified 40 times from cytosols. CSF-2 was a highly stable molecule, being neither inactivated nor dissociated at pH 11.5 or by 4M-NaCl and LiCl and 8 M-urea. It was also resistant to RNAse treatment. However, CSF-2 could be broken down into small peptides of variable sizes by trypsin, alpha-chymotrypsin, and papain, but not by S. aureus V8 protease, although it was less sensitive to proteases than CSF-1. The dose-dependency test showed that the activity of CSF-2 is independent of its concentration and that an amount of CSF-2 could cause cleavage arrest earlier when injected into a blastomere in a larger volume.

PRELIMINARY CHARACTERIZATION OF AN ANDROGEN-MACROMOLECULAR COMPLEX FROM THE RAT VENTRAL PROSTATE

1969 ◽  
Vol 62 (1) ◽  
pp. 153-164 ◽  
Author(s):  
Olav Unhjem ◽  
Kjell J. Tveter ◽  
Asbjørn Aakvaag
Keyword(s):  
Proteolytic Enzymes ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Sucrose Density Gradient ◽  
Ventral Prostate ◽  
Macromolecular Complex ◽  
Sucrose Density Gradient Centrifugation

ABSTRACT Following administration of (1,2-3H)-testosterone to castrated rats or incubation of prostatic tissue with the same steroid, a gel filtration technique has been used for the isolation of a soluble steroid-macromolecular complex from the tissues. Subsequent steroid analyses revealed that 5α-androstan-17β-ol-3-one was the major component associated with the macromolecules both in the in vivo and by in vitro experiments. The complex is destroyed by proteolytic enzymes like trypsin and pronase, but is unaffected by DNase and RNase. The complex is excluded from G-200 as well as P-300 gel beds. By sucrose density gradient centrifugation two macromolecular components were found associated with radioactivity. The largest component had a sedimentation coefficient of 9.3 S and probably corresponds to the macromolecular complex demonstrated by gel filtration, whereas the smaller component had a sedimentation coefficient of 4.5 S and might represent an association of steroids with serum albumin.

Deoxyribonucleic acid polymerase from nuclei of rat intestinal mucosa

1970 ◽  
Vol 48 (5) ◽  
pp. 529-536 ◽  
Author(s):  
F. Y. T. Leung ◽  
S. H. Zbarsky
Keyword(s):  
Dna Polymerase ◽  
Intestinal Mucosa ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Molecular Size ◽  
Sucrose Density Gradient ◽  
Polymerase Activity ◽  
Sucrose Density Gradient Centrifugation ◽  
Dna Template

An extract with DNA polymerase activity was prepared from nuclei of intestinal mucosa of the rat. Chromatography of the crude extract on DEAE-cellulose yielded three enzymically active fractions: I, II, and III. Each fraction could be resolved further into two components with DNA polymerase activity by rechromatography on smaller columns of DEAE-cellulose. A similar result was obtained by gel filtration of fraction II material on Sephadex G-150. The result of sucrose density gradient centrifugation of the fractions obtained by gel filtration suggested that each still consisted of a mixture of proteins with DNA polymerase activity. The approximate molecular weights of the active proteins, estimated by comparison with marker proteins, ranged from 25 000 to 300 000. Partially purified DNA polymerase (fraction II) required for activity the four deoxyribonucleoside triphosphates, Mg2+, 2-mercaptoethanol, and DNA template. The optimum pH for activity was 8.0 in Tris–HCl buffer and 7.4 in phosphate buffer. The two components obtained by gel filtration of fraction II differed in their requirements for DNA template. The one of smaller molecular size was more active with native DNA whereas the larger was equally active with either native or heat-denatured DNA.

scholarly journals VirB7 Lipoprotein Is Exocellular and Associates with the Agrobacterium tumefaciens T Pilus

2001 ◽  
Vol 183 (12) ◽  
pp. 3642-3651 ◽  
Author(s):  
Vitaliya Sagulenko ◽  
Evgeniy Sagulenko ◽  
Simon Jakubowski ◽  
Elena Spudich ◽  
Peter J. Christie
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Cell Surface ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Sucrose Density Gradient ◽  
Effector Proteins ◽  
Cross Linking ◽  
Sucrose Density Gradient Centrifugation ◽  
Type Iv ◽  
Outer Membrane Lipoprotein

ABSTRACT Agrobacterium tumefaciens transfers oncogenic T-DNA and effector proteins to plant cells via a type IV secretion pathway. This transfer system, assembled from the products of the virBoperon, is thought to consist of a transenvelope mating channel and the T pilus. When screened for the presence of VirB and VirE proteins, material sheared from the cell surface of octopine strain A348 was seen to possess detectable levels of VirB2 pilin, VirB5, and the VirB7 outer membrane lipoprotein. Material sheared from the cell surface of mostvirB gene deletion mutants also possessed VirB7, but not VirB2 or VirB5. During purification of the T pilus from wild-type cells, VirB2, VirB5, and VirB7 cofractionated through successive steps of gel filtration chromatography and sucrose density gradient centrifugation. A complex containing VirB2 and VirB7 was precipitated from a gel filtration fraction enriched for T pilus with both anti-VirB2 and anti-VirB7 antiserum. Both the exocellular and cellular forms of VirB7 migrated as disulfide-cross-linked dimers and monomers when samples were electrophoresed under nonreducing conditions. A mutant synthesizing VirB7 with a Ser substitution of the lipid-modified Cys15 residue failed to elaborate the T pilus, whereas a mutant synthesizing VirB7 with a Ser substitution for the disulfide-reactive Cys24 residue produced very low levels of T pilus. Together, these findings establish that the VirB7 lipoprotein localizes exocellularly, it associates with the T pilus, and both VirB7 lipid modification and disulfide cross-linking are important for T-pilus assembly. T-pilus-associated VirB2 migrated in nonreducing gels as a monomer and a disulfide-cross-linked homodimer, whereas cellular VirB2 migrated as a monomer. A strain synthesizing a VirB2 mutant with a Ser substitution for the reactive Cys64 residue elaborated T pilus but exhibited an attenuated virulence phenotype. Dithiothreitol-treated T pilus composed of native VirB2 pilin and untreated T pilus composed of the VirB2C64S mutant pilin distributed in sucrose gradients more predominantly in regions of lower sucrose density than untreated, native T pili. These findings indicate that intermolecular cross-linking of pilin monomers is not required for T-pilus production, but cross-linking does contribute to T-pilus stabilization.

scholarly journals Hydrodynamic and pharmacological characterization of putative α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate-sensitive l-glutamate receptors solubilized from pig brain

1994 ◽  
Vol 300 (2) ◽  
pp. 365-371 ◽  
Author(s):  
T Y Wu ◽  
Y C Chang
Keyword(s):  
Binding Sites ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Glutamate Binding ◽  
Stokes Radius ◽  
Triton X

L-[3H]Glutamate binding sites with characteristics resembling that of membrane-bound alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate-subtype L-glutamate receptors have been solubilized from pig brain synaptic junctions by Triton X-114. Binding of [3H]AMPA to these soluble sites in the presence of KSCN results in a curvilinear Scatchard plot that can be resolved into a high-affinity component and a low-affinity component. These Triton-X-114-solubilized sites can be further separated into two species of binding sites by gel-filtration chromatography or sucrose-density-gradient centrifugation. The pharmacological profiles of these two species of binding site are almost identical, and the rank orders of potency for glutamatergic drugs in displacing L-[3H]glutamate binding to these sites are quisqualate > 6,7-dinitroquinoxaline-2,3-dione > 6-cyano-7-nitroquinoxaline-2,3-dione > AMPA > L-glutamate > kainate >> N-methyl-D-aspartate = L-2-amino-4-phosphonobutyrate. Both sites are found to bind [3H]AMPA, and in the presence of KSCN the binding activities are significantly enhanced. Analysis of the hydrodynamic behaviour of these binding sites by sucrose-density-gradient centrifugation in H2O- and 2H2O-based solvents and gel-filtration chromatography has revealed that one of these sites (Stokes radius 8.3 nm, sedimentation coefficient 18.5 S) consists of 562 kDa protein and 281 kDa detergent, and the other site (Stokes radius 9.6 nm, sedimentation coefficient 13.4 S) consists of 352 kDa protein and 569 kDa detergent. Frictional coefficients of these sites indicate that these receptor-detergent complexes are asymmetrical in structure, consistent with large transmembrane proteins.

scholarly journals Alteration of hepatic glucocorticoid receptor stability and nuclear binding in vitro by citrate

1983 ◽  
Vol 210 (1) ◽  
pp. 259-263 ◽  
Author(s):  
J Hubbard ◽  
M Kalimi
Keyword(s):  
Glucocorticoid Receptor ◽  
Glucocorticoid Receptors ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Deae Cellulose ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Nuclear Binding ◽  
Wide Range

Citrate greatly stabilized rat hepatic unbound glucocorticoid receptors in cell-free conditions at 4 degrees C with optimal effectiveness at 5-15 mM. Control receptors were inactivated at 4 degrees C with a half-life of less than 12 h. However, in the presence of 10 mM-citrate, unbound receptors were almost completely stabilized for 48 h at 4 degrees C. Citrate at a concentration of 1-2 mM yielded half-maximal stabilization. The stabilizing effect of citrate was rather specific, as succinate, alpha-oxoglutarate, oxaloacetate, malate and pyruvate had no apparent stabilizing action. Citrate stabilized receptors over a wide range of H+ concentrations, with complete protection between pH 6.5 and 8.5. In addition, citrate appeared to have a significant effect on glucocorticoid-receptor complex activation into a nuclear binding form. Thus 5-10 mM-citrate enhanced nuclear binding, with optimal activation achieved at 10 mM concentration. As analysed by sucrose-density-gradient centrifugation and DEAE-cellulose chromatography, no apparent change was observed in the physical characteristics of the glucocorticoid receptor in the presence of citrate.

scholarly journals Separation and Paired Proteome Profiling of Plant Chloroplast and Cytoplasmic Ribosomes

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 892
Author(s):  
Alexandre Augusto Pereira Firmino ◽  
Michal Gorka ◽  
Alexander Graf ◽  
Aleksandra Skirycz ◽  
Federico Martinez-Seidel ◽  
...  
Keyword(s):  
Ribosome Biogenesis ◽  
Gradient Centrifugation ◽  
Leaf Tissue ◽  
Proteome Analysis ◽  
Sucrose Density Gradient ◽  
Cross Linking ◽  
Sucrose Density Gradient Centrifugation ◽  
Cytoplasmic Ribosome ◽  
Plant Chloroplast

Conventional preparation methods of plant ribosomes fail to resolve non-translating chloroplast or cytoplasmic ribosome subunits from translating fractions. We established preparation of these ribosome complexes from Arabidopsis thaliana leaf, root, and seed tissues by optimized sucrose density gradient centrifugation of protease protected plant extracts. The method co-purified non-translating 30S and 40S ribosome subunits separated non-translating 50S from 60S subunits, and resolved assembled monosomes from low oligomeric polysomes. Combining ribosome fractionation with microfluidic rRNA analysis and proteomics, we characterized the rRNA and ribosomal protein (RP) composition. The identity of cytoplasmic and chloroplast ribosome complexes and the presence of ribosome biogenesis factors in the 60S-80S sedimentation interval were verified. In vivo cross-linking of leaf tissue stabilized ribosome biogenesis complexes, but induced polysome run-off. Omitting cross-linking, the established paired fractionation and proteome analysis monitored relative abundances of plant chloroplast and cytoplasmic ribosome fractions and enabled analysis of RP composition and ribosome associated proteins including transiently associated biogenesis factors.

Enhancing Effect of Surfactant and Protein on Hydrolysis of Thymolphthalein Monophosphate by Purified Prostatic Acid Phosphatase

1975 ◽  
Vol 21 (12) ◽  
pp. 1761-1765 ◽  
Author(s):  
Andras G Foti ◽  
Harvey Herschman ◽  
J Fenimore Cooper ◽  
Hedi imFeld
Keyword(s):  
Acid Phosphatase ◽  
Serum Proteins ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Prostatic Acid Phosphatase ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Brij 35 ◽  
Hydrolysis Of ◽  
Protein Bovine Serum Albumin

Abstract Purified prostatic acid phosphatase catalyzes the hydrolysis of thymolphthalein monophosphate 10-fold faster if an optimal concentration of Brij 35 (a wetting agent) or protein (bovine serum albumin or human serum proteins) is present. Results of gel filtration, dialysis, and sucrose density-gradient centrifugation analysis suggest that the substrate must combine with detergent or protein before the enzyme can catalyze its hydrolysis.

DEMONSTRATION OF A CYTOPLASMIC RECEPTOR PROTEIN FOR OESTROGEN IN THE CANINE PROSTATE GLAND

1978 ◽  
Vol 78 (1) ◽  
pp. 131-139 ◽  
Author(s):  
N. CHAISIRI ◽  
Y. VALOTAIRE ◽  
BRONWEN A. J. EVANS ◽  
C. G. PIERREPOINT
Keyword(s):  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Prostate Gland ◽  
Sedimentation Coefficient ◽  
Sucrose Density Gradient ◽  
Receptor Protein ◽  
Receptor Complex ◽  
Binding Properties ◽  
Sucrose Density Gradient Centrifugation ◽  
A Value

A receptor protein that selectively binds oestrogens has been demonstrated in the cytosol of the canine prostate gland. The steroid–receptor complex was found to have a sedimentation coefficient of 4–5 S with respect to bovine serum albumin after sucrose density-gradient centrifugation. The high affinity and low capacity of the protein for oestrogens was indicated by displacement studies, which gave a value of 3·8 ± 1·53 (s.d.) × 10−10 mol/l for the dissociation constant. A metastasizing prostatic tumour was also shown to possess this receptor, with binding properties similar to those exhibited by the receptor in normal prostatic cytosol. The implications of these findings are discussed with regard to normal prostatic function in the dog and the virtually inevitable advent of prostatic hyperplasia with age in this species.

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