scholarly journals Gel-electrophoretic identification of hen brain neurotoxic esterase, labelled with tritiated di-isopropyl phosphorofluoridate

1981 ◽  
Vol 199 (2) ◽  
pp. 323-333 ◽  
Author(s):  
D G Williams ◽  
M K Johnson
Keyword(s):  
Active Site ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
The Other ◽  
Particulate Fraction ◽  
Molecular Weights ◽  
The Brain ◽  
Neurotoxic Esterase

The particulate fraction from hen brain was labelled with [3H]di-isopropyl phosphorofluoridate (DiPF) and separated by polyacrylamide-gel electrophoresis. Four radioactive protein bands (1--4) of molecular weights 155000, 92000, 60000, and 30000 were resolved. Most of the labelling of bands 2, 3 and 4 was inhibited by preincubation with Paraoxon. The residue in band 4 was sensitive to pH 5.2. Successive treatments with Paraoxon and pH 5.2 resulted in the abolition of bands 3 and 4. Bands 1 and 2 contained one and two polypeptides respectively, whose labelling was sensitive to Mipafox, but one, in band 2, was sensitive to higher concentrations of Paraoxon. The concentrations of the other two polypeptides were 6.7 and 1.95 pmol of DiPF bound/g of brain in bands 1 and 2 respectively. Both were as sensitive to Mipafox as neurotoxic esterase and were also sensitive to phenyl benzylcarbamate. 4-Nitrophenyl di-n-pentylphosphinate given in vivo inhibited neurotoxic esterase and the labelling of the band-1 polypeptide by 82% and 84% respectively, but inhibited the labelling of the band 2 polypeptide by 51%. The phosphinate in vitro produced 98% inhibition of the labelling of the band-1 polypeptide, with only 26% inhibition of the band-2 polypeptide, under conditions sufficient to inhibit neurotoxic esterase totally. Both neurotoxic esterase and the band-1 polypeptide were found in the forebrain at 1.74-fold their concentration in the rest of the brain, whereas the band-2 polypeptide was uniformly distributed. The evidence indicates that the Mipafox-sensitive polypeptide in band 1 is the [3H]DiPF-labelled active-site subunit of neurotoxic esterase. The catalytic-centre activity of the enzyme for phenyl valerate hydrolysis was found to be 2.6 x 10(5) min-1.

Platelet Microtubule Subunit Proteins

1979 ◽  
Vol 42 (05) ◽  
pp. 1630-1633 ◽  
Author(s):  
A G Castle ◽  
N Crawford
Keyword(s):  
Epithelial Cells ◽  
Gel Electrophoresis ◽  
Blood Platelets ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Lens Epithelial Cells ◽  
Molecular Weights ◽  
Kinetics Of ◽  
Microtubular Structures

SummaryBlood platelets contain microtubule proteins (tubulin and HMWs) which can be polymerised “in vitro” to form structures which resemble the microtubules seen in the intact platelet. Platelet tubulin is composed of two non-identical subunits a and p tubulin which have molecular weights around 55,000 but can be resolved in alkaline SDS-polyacrylamide gel electrophoresis. These subunits associate as dimers with sedimentation coefficients of about 5.7 S although it is not known whether the dimer protein is a homo- or hetero-dimer. The dimer tubulin binds the anti-mitotic drug colchicine and the kinetics of this binding are similar to those reported for neurotubulins. Platelet microtubules also contain two HMW proteins which appear to be essential and integral components of the fully assembled microtubule. These proteins have molecular weights greater than 200,000 daltons. Fluorescent labelled antibodies to platelet and brain tubulins stain long filamentous microtubular structures in bovine lens epithelial cells and this pattern of staining is prevented by exposing the cells to conditions known to cause depolymerisation of cell microtubules.

In-vivo and in-vitro secretion of prolactin by lactating rat adenohypophyses as a function of intracellular age

1984 ◽  
Vol 101 (1) ◽  
pp. 27-32 ◽  
Author(s):  
F. Mena ◽  
G. Martínez-Escalera ◽  
C. Clapp ◽  
C. E. Grosvenor
Keyword(s):  
Pituitary Gland ◽  
Incubation Period ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Pituitary Glands ◽  
H 26

ABSTRACT Adenohypophysial prolactin of lactating rats was pulse-labelled by [3H]leucine injected i.v. at the time of removal of the pups. The [3H]prolactin concentration in the pituitary gland, analysed by polyacrylamide-gel electrophoresis, progressively fell as the time from labelling to removal of the pituitary gland increased from 8 to 24 h, which suggests that there was a loss of hormone as it aged within the gland. Suckling effectively provoked the depletion–transformation of total and [3H]prolactin (extracted at pH 7·2) when applied after 8 h but not when applied after either 16 or 24 h after removing the pups. In rats whose pups were removed for 8 h, suckling also depleted–transformed [3H]prolactin labelled 4 h, but not that labelled 1 h before suckling. The pituitary glands of other lactating rats were labelled with [3H]leucine injected i.v. at various times before removing the glands and incubating them in medium 199. The secretion into the medium of [3H]prolactin labelled either 4, 8, 16 or 24 h beforehand was maximal during the first 30 min then declined from 30 to 240 min of incubation. However, secretion of prolactin labelled 1 h and 10 min beforehand reached a maximum after 0·5–1 h and 2 h of incubation respectively, then remained constant during the remainder of the 4-h incubation period. The total 4-h secretion of [3H]prolactin was greatest (65% of preincubation concentration) from those glands labelled 4 h before in contrast to those labelled 10 min (15%) or 1 (38%), 8 (34%), 16 (18%) or 24 h (26%) before incubation. Taken together, these data suggest that prolactin synthesized 4 h earlier is more likely to be released in response to physiological stimuli than is more recently formed prolactin or prolactin which has remained in the pituitary gland for 16 h or longer. J. Endocr. (1984) 101, 27–32

scholarly journals Characterization of proteins from the cytoskeleton of Giardia lamblia

1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Giardia Lamblia ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Molecular Size ◽  
Molecular Weights

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.

scholarly journals In vivo radiolabeling of platelet proteins: a new method with identification of platelet factor XIII

Blood ◽  
1980 ◽  
Vol 55 (4) ◽  
pp. 559-563 ◽  
Author(s):  
DM Rider ◽  
RP McDonagh ◽  
J McDonagh
Keyword(s):  
Gel Electrophoresis ◽  
Factor Xiii ◽  
Soluble Fraction ◽  
Polyacrylamide Gel Electrophoresis ◽  
Fold Increase ◽  
Platelet Factor ◽  
Intravenous Injections ◽  
Molecular Weights ◽  
The Third

Abstract A method for radiolabeling platelets in vivo was developed in which 3H- arginine was injected into the bone marrow of normal dogs. On the third day after injection, a maximum of 6%--7% of the radioactivity had been incorporated into the total platelet mass. This method of isotope administration resulted in a 50--60-fold increase in maximum uptake of radiolabel by platelets, as compared to values obtained by others using intravenous injections of various radioactive compounds. Tritium- labeled platelets were harvested from the animals and then were washed to remove unbound 3H-arginine. On polyacrylamide gel electrophoresis 7 labeled protein bands, with molecular weights ranging from 29,000to 132,000, were obtained from the platelet-soluble fraction. One 3H- containing protein with a molecular weight of 81,000 was identified immunologically and enzymatically as platelet factor XIII.

II. Mitt.: Auflösung der Chromoproteidfraktion aus Rattenleber-Ribosomen mit Hilfe der Polyacrylamidgel-Elektrophorese

1970 ◽  
Vol 25 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Wolfram Domschke ◽  
Jürgen G. Meyer-Bertenrath
Keyword(s):  
Gel Electrophoresis ◽  
Ribosomal Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
The Other ◽  
Blue Staining ◽  
Ribosomal Subunits ◽  
Molecular Weights ◽  
The One ◽  
Liver Ribosomes

After preparation of a coloured protein component containing iron from rat liver ribosomes 1 this fraction was submitted to detailed analysis by means of polyacrylamide gel electrophoresis. Thus it may be separated into one main and two secondary bands, which do not contain RNA detectable by methylene blue staining. The ferric content of all bands can be demonstrated by staining with 2,4-dinitroso-1,3-naphthalenediol 2. These bands are to be found in the large ribosomal subunits as well as in the small one in qualitative conformity, they differ, however, in their quantitative relations to each other depending on origin. LiCl-extraction as described for the preparation of ribosomal proteins causes dissociation of the chromoproteid fraction into six bands possessing lower molecular weights each than the original bands.The chromoproteids, localized in the large ribosomal subunits on the one hand and in the small subunits on the other hand were prepared differentiatedly by gel filtration. Results show the chromoproteid represented in the 57-S-subunit on a bigger scale than the nucleoproteid part, on the contrary, the 29-S-subunit is constructed of RNA-containing material preferably.

Identification of D-Dimer-E Complex in Disseminated Intravascular Coagulation (DIC)

1979 ◽  
Author(s):  
A.N. Whitaker ◽  
E.A. Rowe ◽  
P.P. Masci ◽  
P.J. Gaffney
Keyword(s):  
Gel Electrophoresis ◽  
Degradation Products ◽  
Polyacrylamide Gel Electrophoresis ◽  
Stable Complex ◽  
Fibrin Degradation Products ◽  
Pneumococcal Sepsis ◽  
D Antigen ◽  
D Dimer

D-dimer (D2), a product of the plasmin lysis of cross-linked (XL) fibrin, but not of non-XL fibrin or fibrinogen, has been identified in the plasma of patients with DIC due to amniotic fluid embolism. In vitro, D is involved with fragment E as a stable complex (D2-E) but D2 -E has not been identified in vivo before. Fibrin degradation products (FDP) were studied in a patient having fulminant postsplenectomy pneumococcal sepsis and DIC, by immunoprecipitation with anti-fibrinogen (f) and anti-fragment E and characterization by SDS polyacrylamide gel electrophoresis (PAGE). With both antisera soluble HMW fibrin complexes, D2 and E but no X, Y or D were obtained from serum. D2 and E were identified in the supernatant after removing partially XL HMW complexes and fibrinogen from plasma with 2.5 M β-alanine. The presence D antigen in the D2-E complex precipitated by monospecific anti-E was confirmed by crossed Ag-Ab electrophoresis. Crossed Ag-Ab electrophoresis of serum in agarose gave E peaks of slow mobility and no fast-moving free E was found. Thus, D2-E complex exists in vivo and its easy identification, proving the lysis of XL fibrin, would be of value in studying thrombosis. D2-E complex has been identified in other patients with sepsis but at lower concentrations than described above.

scholarly journals Alpha 2-macroglobulin binds and inhibits activated protein C

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2283-2290 ◽  
Author(s):  
H Hoogendoorn ◽  
CH Toh ◽  
ME Nesheim ◽  
AR Giles
Keyword(s):  
Complex Formation ◽  
Active Site ◽  
Metal Ion ◽  
Protein C ◽  
Binding Protein ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
High Molecular Weight Complex

In previous studies using a nonhuman primate model of Protein C (PC) activation in vivo, immunoblotting showed substantial amounts of activated PC (APC) in a high molecular weight complex with what was presumed to be a previously unrecognized APC binding protein. This APC complex can also be formed in citrated plasma in vitro. It is of low electrophoretic mobility, sodium dodecyl sulfate (SDS) stable, with an apparent Mr of 320 Kd. Its purification from human plasma was accomplished using barium citrate adsorption, sequential polyethylene glycol (PEG) precipitations, diethylaminoethyl sepharose chromatography, AcA-34 gel filtration, and zinc-chelate affinity chromatography. This was monitored by subjecting the fractions to nondenaturing polyacrylamide gel electrophoresis (PAGE), transfer to polyvinylidene-difluoride membranes, and probing with 125I-labeled human APC. The purified APC-binding protein was homogeneous by SDS-PAGE with an Mr of 275 Kd. Its identity as alpha 2-macroglobulin (alpha 2M) was demonstrated immunochemically. Complex formation between alpha 2M and APC was found to be almost completely inhibited by EDTA, but to a lesser extent by citrate. Complex formation could also be prevented by active site inhibition with D-Phenylalanyl-L-Prolyl-L-Arginine- Chloromethyl Ketone (PPACK) or pretreatment of alpha 2M with methylamine. Incubation of APC (33 nmol/L) with alpha 2M (1 mumol/L) resulted in time-dependent inhibition of APC anticoagulant activity when measured using an activated partial thromboplastin time based APC assay. These data show that alpha 2M binds and inhibits APC in vitro and the interaction is both metal-ion and active-site dependent, requiring functionally intact alpha 2M. As the complexes formed in vitro comigrate electrophoretically with those observed in vivo after PC activation, it is suggested that alpha 2M is a physiologically relevant inhibitor involved in the processing of APC in vivo.

Studies of the Metabolism of Asialotransferrins: Evidence that Transferrin Does not Undergo Desialylation in Vivo

1974 ◽  
Vol 46 (6) ◽  
pp. 763-774
Author(s):  
K.-L. Wong ◽  
P. A. Charlwood ◽  
M. W. C. Hatton ◽  
E. Regoeczi
Keyword(s):  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Biological Significance ◽  
Polyacrylamide Gel ◽  
Fractional Catabolic Rate ◽  
Sialic Acid Content ◽  
Catabolic Rate ◽  
Bovine Transferrin

1. Experiments are reported which aimed at determining whether transferrin loses sialyl residues from the carbohydrate side-chains during the biological lifetime of the molecule. To explore this possibility, transferrin fractions of relatively high sialic acid content (referred to as sialotransferrin) were prepared from purified rabbit and bovine transferrin by preparative polyacrylamide-gel electrophoresis. After labelling with 125I, the preparations were injected into a group of three rabbits each. From the plasma samples obtained between 1 h and 6–8 days after injection, transferrin was partially purified, mixed with 131I-labelled asialotransferrin of the corresponding species and run in preparative polyacrylamide-gel electrophoresis. In each specimen examined, the 125I radioactivity migrated ahead of the marker asialotransferrin, and no portion of the dose was detected with the electrophoretic mobility of asialotransferrin. 2. Evidence is presented that bovine transferrin desialylated in vitro remains detectable in the plasma of rabbits for intervals which are comparable with those found in previous studies with rabbit asialotransferrin. 3. A mathematical model is described for the computation of asialo- to sialotransferrin radioactivity ratios in the plasma, continuous desialylation of pulse-injected sialotransferrin being assumed. Calculations were made at various hypothetical rates of desialylation. 4. On the basis of the experimental data and the model it is concluded that transferrin (both rabbit and bovine) is not subjected to systematic desialylation in rabbits. Random desialylation of some transferrin could take place at rates less than 5% of the fractional catabolic rate of transferrin, which would be without any biological significance.

EFFECTS OF GONADOTROPHINS AND CYCLIC 3′,5′-AMP ON IN VITRO INCORPORATION OF [3H]URIDINE INTO RNA OF THE PREPUBERTAL RAT OVARY

1973 ◽  
Vol 72 (4) ◽  
pp. 771-785 ◽  
Author(s):  
Jan Jarlstedt ◽  
Lars Nilsson ◽  
Lars Hamberger ◽  
Kurt Ahrén
Keyword(s):  
Cyclic Nucleotide ◽  
Gel Electrophoresis ◽  
Incubation Medium ◽  
Polyacrylamide Gel Electrophoresis ◽  
Labelling Pattern ◽  
Total Rna ◽  
Rat Ovary ◽  
Prepubertal Rats

ABSTRACT In vivo and in vitro effects of FSH and LH on in vitro incorporation of [3H]uridine into RNA of the prepubertal rat ovary have been studied. RNA was fractionated with composite agarose-polyacrylamide gel electrophoresis. When FSH was injected into the prepubertal rats 4 h before incubation of the ovaries, the incorporation of labelled uridine into total RNA was decreased showing relatively more radioactivity concentrated to the RNA fractions lighter than 28S as compared to the controls. These effects were not seen when FSH was added to the incubation medium in vitro. When LH was added in vitro to the isolated ovaries a higher percentage of incorporated radioactivity was concentrated in the RNA fractions heavier than 28S without any change in the incorporation of [3H]uridine into total RNA. LH administered in vivo 30 min before incubation of the ovaries gave the same change in the labelling pattern between the RNA fractions as LH in vitro but in addition showed a decreased incorporation of radioactivity into total RNA. The in vitro effects of cyclic 3′,5′-AMP were also studied. When prepubertal rat ovaries were incubated in 10 mmol/l of this cyclic nucleotide, the incorporation of [3H] uridine into total RNA was decreased without any change in the labelling pattern.

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