scholarly journals Characterization of a Gi-protein from Trypanosoma cruzi epimastigote membranes

1992 ◽  
Vol 287 (2) ◽  
pp. 443-446 ◽  
Author(s):  
O A Coso ◽  
A Díaz Añel ◽  
H Martinetto ◽  
J P Muschietti ◽  
M Kazanietz ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Pertussis Toxin ◽  
Polyclonal Antibodies ◽  
Gel Filtration ◽  
Binding Activity ◽  
Gi Protein ◽  
Liver Membranes ◽  
Blocking Capacity ◽  
Polypeptide Band

A guanosine 5′-[gamma-[35S]thio]triphosphate-binding activity was detergent-extracted from Trypanosoma cruzi membranes. This binding activity was co-eluted from gel-filtration columns with a factor which, in a heterologous reconstitution system, blocks glucagon stimulation of adenylate cyclase activity in liver membranes. ADP-ribosylation of these membranes by pertussis toxin eliminated this blocking capacity. Incubation of T. cruzi membranes with activated pertussis toxin and [adenylate-32P]NAD+ led to the incorporation of radioactivity into a labelled product with an apparent M(r) of approx. 43,000. Crude membranes were electrophoresed on SDS/polyacrylamide gels and analysed, by Western blotting, with GA/1 anti-alpha common, AS/7 anti-alpha t, anti-alpha i1 and anti-alpha i2 polyclonal antibodies. These procedures led to the identification of a specific polypeptide band of about 43 kDa. Another polypeptide reacting with the SW/1 anti-beta antibody, of about 30 kDa, was also detected in the membrane fraction.

scholarly journals Identification and Characterization of PtlC, an Essential Component of the Pertussis Toxin Secretion System

1999 ◽  
Vol 67 (2) ◽  
pp. 754-759 ◽  
Author(s):  
David M. Cook ◽  
Karen M. Farizo ◽  
Drusilla L. Burns
Keyword(s):  
Pertussis Toxin ◽  
Polyclonal Antibodies ◽  
Apparent Molecular Weight ◽  
Dominant Negative ◽  
Proper Function ◽  
Cell Extracts ◽  
Toxin Secretion ◽  
Identification And Characterization ◽  
Negative Phenotype

ABSTRACT PtlC is a member of a set of proteins necessary for the secretion of pertussis toxin (PT) from Bordetella pertussis. Using polyclonal antibodies specific for PtlC, we identified PtlC as a protein with an apparent molecular weight of 85,000 that localizes to the membrane fraction of bacterial cell extracts. We found that a mutant strain of B. pertussis that contains an in-frame deletion in ptlC is unable to secrete PT and that PT secretion is fully restored by expressing ptlC intrans, indicating that PtlC is essential for transport of PT across the bacterial membrane(s). PT secretion was inhibited in wild-type B. pertussis after introduction of a plasmid expressing a mutant ptlC altered in the putative nucleotide-binding region, suggesting that this region of PtlC is essential for proper function. Moreover, the observed dominant negative phenotype suggests that PtlC either functions as a multimer or interacts with some other component(s) necessary for secretion of PT.

scholarly journals COLCEMID INHIBITION OF CELL GROWTH AND THE CHARACTERIZATION OF A COLCEMID-BINDING ACTIVITY IN SACCHAROMYCES CEREVISIAE

1972 ◽  
Vol 55 (2) ◽  
pp. 355-367 ◽  
Author(s):  
James E. Haber ◽  
John G. Peloquin ◽  
Harlyn O. Halvorson ◽  
Gary G. Borisy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gel Filtration ◽  
Culture Conditions ◽  
Binding Activity ◽  
Affinity Constant ◽  
Binding Substance ◽  
Related Drug ◽  
Antimitotic Drug ◽  
The Difference

Under restricted culture conditions, the growth and division of Saccharomyces cerevisiae was inhibited by the antimitotic drug Colcemid; in contrast, the related drug colchicine had no effect. The difference in the sensitivity of yeast to these two agents was not dependent on their ability to permeate the cell but rather reflected an inherent difference in the affinity of the two drugs for a cellular-binding site. The binding moiety was characterized by gel filtration as a macromolecule of approximately 110,000 mol wt with an affinity constant for Colcemid of 0.5 x 104 liters per mole; in addition, this macromolecule was retained by diethylaminoethyl (DEAE) ion exchangers. On the basis of these properties, the Colcemid-binding substance in S. cerevisiae cells was provisionally identified as microtubule subunits.

Na+-K+-ATPase-G protein coupling in myocardial sarcolemma: separation and reconstitution

1991 ◽  
Vol 261 (4) ◽  
pp. 87-91
Author(s):  
Mikhail P. Danilenko ◽  
Vera C. Turmukhambetova ◽  
Oleg V. Yesirev ◽  
Vsevolod A. Tkachuk ◽  
Mikhail P. Panchenko
Keyword(s):  
Atpase Activity ◽  
Pertussis Toxin ◽  
Gel Filtration ◽  
Protein S ◽  
Half Maximum ◽  
Inhibitory Effects ◽  
Cardiac Sarcolemma ◽  
Dependent Inhibition ◽  
Gi Protein ◽  
Zwitterionic Detergent

The cholinergic agonist carbachol produces a concentration-dependent (half-maximum inhibitory concentration = 0.9 μM) decrease in the Na+-K+-adenosine triphosphatase (ATPase) activity of rabbit cardiac sarcolemma that occurred only in the presence of guanosine 5'-[-thio]triphosphate (0.1 μM GTPS) and reached 40% inhibition. The inhibition is blocked by the muscarinic receptor antagonist atropine (10 μM) and is abolished in sarcolemma treated with pertussis toxin (20 μg/ml) in the presence of 100 μM NAD. GTPS alone reduces Na+–K+-ATPaseactivity by 45% (half-maximum inhibitory = 1 μM). The apparent affinity of the enzyme for GTPS is increased 10-fold in the presence of 1 μM carbachol. In sarcolemma solubilized with the zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS, 10 mM), the GTPS-dependent inhibition of the Na+-K+-ATPase is also observed. Gel filtration of a CHAPS extract of sarcolemma on a Sepharose CL–6B column resulted in a separation of Na+-K+-ATPase and pertussis toxin-sensitive Gi activities. Na+-K+-ATPase activity that was separated on the column lost its sensitivity to the inhibitory action of guanine nucleotides. Inhibitory effects (20–30%) of guanosine 5'-triphosphate analogues [Gpp(NH)p, GTPS, or Gpp(CH2)p] at micromolar concentrations were restored when the Na+-K+-ATPase activity was recombined with fractions that contained the pertussis toxin-sensitive Gi protein(s). Similar concentrations of guanosine 5'-triphosphate, guanosine 5'-diphosphate, guanosine-5'-[β-thio]diphosphate, or App(NH)p were unable to induce the Gi protein-mediated attenuation of Na+-K+-ATPase activity in the reconstitution system. These results suggest that a pertussis toxin-sensitive Gi protein may act as a transducer of the inhibitory hormonal signals on Na+-K+-ATPase in the sarcolemma. cardiac sarcolemma

scholarly journals Characterization of proliferating cell nuclear antigen recognized by autoantibodies in lupus sera.

1984 ◽  
Vol 159 (4) ◽  
pp. 981-992 ◽  
Author(s):  
Y Takasaki ◽  
D Fishwild ◽  
E M Tan
Keyword(s):  
Lupus Erythematosus ◽  
Proliferating Cell Nuclear Antigen ◽  
Gel Filtration ◽  
Nuclear Antigen ◽  
Light Chains ◽  
Blast Transformation ◽  
Single Polypeptide ◽  
Proliferating Cell ◽  
Polypeptide Band

A nuclear antigen associated with cell proliferation (proliferating cell nuclear antigen [PCNA]) and blast transformation is recognized by autoantibodies in the sera of some patients with systemic lupus erythematosus. Using this autoantibody as a reagent, PCNA was purified 120-fold by ammonium sulfate fractionation, DEAE chromatography, and Sephadex G200 gel filtration. The antigenicity of PCNA was sensitive to trypsin but resistant to ribonuclease and deoxyribonuclease, suggesting that the antigenic determinant resided in protein and not nucleic acids. PCNA was inactivated at 56 degrees C for 30 min. Isoelectrophoretic focusing showed that the pI was 4.8. Analysis of immunoprecipitates on polyacrylamide gels showed the presence of IgG heavy and light chains and a single polypeptide band of 33,000 mol wt. This polypeptide band was the reactive antigen in immunoblotting (Western transfer) assays.

scholarly journals Purification and partial characterization of four proteins from human parotid saliva

1971 ◽  
Vol 123 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Anders Bennick ◽  
George E. Connell
Keyword(s):  
Serum Proteins ◽  
Protein A ◽  
Gel Filtration ◽  
Binding Activity ◽  
Significant Activity ◽  
Parotid Saliva ◽  
Polyacrylamide Electrophoresis ◽  
Ph Range ◽  
Human Parotid Saliva

Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3–10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, β-glucuronidase, β-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.

scholarly journals G-protein from Medicago sativa: functional association to photoreceptors

1993 ◽  
Vol 291 (2) ◽  
pp. 383-388 ◽  
Author(s):  
J P Muschietti ◽  
H E Martinetto ◽  
O A Coso ◽  
M D Farber ◽  
H N Torres ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Cholera Toxin ◽  
G Protein ◽  
Pertussis Toxin ◽  
Polyclonal Antibodies ◽  
Red Light ◽  
Maximal Increase ◽  
Protein Subunits ◽  
Binding Rate ◽  
Polypeptide Band

G-protein subunits were characterized from Medicago sativa (alfalfa) seedlings. Crude membranes and GTP-Sepharose-purified fractions were electrophoresed on SDS/polyacrylamide gels and analysed by Western blotting with 9193 (anti-alpha common) and AS/7 (anti-alpha t, anti-alpha i1 and anti-alpha i2) polyclonal antibodies. These procedures led to the identification of a specific polypeptide band of about 43 kDa. Another polypeptide reacting with the SW/1 (anti-beta) antibody, of about 37 kDa, was also detected. The 43 kDa polypeptide bound specifically [alpha-32P]GTP by a photoaffinity reaction and was ADP-ribosylated by activated cholera toxin, but not by pertussis toxin. Irradiation of etiolated Medicago sativa protoplast preparations at 660 nm for 1 min produced a maximal increase in the guanosine 5′-[gamma-thio]triphosphate (GTP[35S])-binding rate. After this period of irradiation, the binding rate tended to decrease. The effect of a red-light (660 nm) pulse on the binding rate was reversed when it was immediately followed by a period of far-red (> 730 nm) illumination. These results may suggest that activation of GTP[S]-binding rate was a consequence of conversion of phytochrome Pr into the Ptr form.

Purification and characterization of an extracellular exochitinase, β-N-acetylhexosaminidase, from the fungal mycoparasite Stachybotrys elegans

2002 ◽  
Vol 48 (4) ◽  
pp. 311-319 ◽  
Author(s):  
Greg Taylor ◽  
Suha Jabaji-Hare ◽  
Pierre M Charest ◽  
Wajahatullah Khan
Keyword(s):  
Rhizoctonia Solani ◽  
Polyclonal Antibodies ◽  
Polyacrylamide Gel Electrophoresis ◽  
Synthetic Medium ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Biochemical Properties ◽  
Purification And Characterization ◽  
Proteolytic Product

The mycoparasite Stachybotrys elegans produces two exo- and one endo-acting chitinases when grown on chitin. We purified to homogeneity one of the exo-acting chitinases, β-N-acetylhexosaminidase and partially characterized its physical and biochemical properties. The native enzyme has a molecular mass of 120 kDa when determined by gel filtration and 68 kDa by sodium dodecyl sulfate – polyacrylamide gel electrophoresis indicating that the native protein probably occurs as a dimer in solution. The purified β-N-acetylhexosaminidase is most active at pH 5.0 and 40°C and hydrolyzes the ρ-nitrophenyl-N-acetyl-β-D-glucosaminide with apparent Km of 84.6 µM. Polyclonal antibodies raised against the 68-kDa β-N-acetylhexosaminidase (NAG-68) indicated that the antibody is highly specific and recognizes the protein in crude filtrate preparation. This suggests that the protein is a not a proteolytic product of another protein. Western blot analysis showed that the activity of NAG-68 was induced when S. elegans was grown on purified cell wall fragments of its host, Rhizoctonia solani, as well as during antagonistic interaction of the mycoparasite and host when both were grown on synthetic medium with or without supplemental carbon source.Key words: chitinases, protein purification, mycoparsite, Rhizoctonia solani.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Ph Optimum ◽  
Isolation And Characterization ◽  
Ph Range ◽  
Inhibition Studies ◽  
Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

The Immunological Characterization of Human Antibodies to Factor VIII Isolated by Immuno-Affinity Chromatography

1981 ◽  
Vol 45 (01) ◽  
pp. 060-064 ◽  
Author(s):  
M L Kavanagh ◽  
C N Wood ◽  
J F Davidson
Keyword(s):  
Factor Viii ◽  
Affinity Chromatography ◽  
Gel Filtration ◽  
Immunological Characterization ◽  
Human Antibodies ◽  
Heavy Chains ◽  
Light Chain Type ◽  
Antibody Preparations ◽  
Chain Type

SummaryNine human antibodies to factor VIII were isolated from haemophilic plasmas by affinity chromatography and gel filtration and six were subsequently subjected to immunological characterization. Three partially purified preparations were similarly characterized. Eight of the antibodies were characterized as being exclusively IgG and one preparation was found to contain IgM. Seven of the antibodies contained only a single light chain type, four being of type lambda and three of type kappa. Two antibody preparations contained both kappa and lambda light chains. In four of the preparations, only a single heavy chain sub-class could be demonstrated, three of IgG3 and one of IgG4. Of the remainder, three were a mixture of IgG3 and IgG4 sub-classes and one contained both IgG2 and IgG4. IgG sub-classification could not be achieved with the IgM-containing preparation. These results demonstrate a restricted heterogeneity of light and heavy chains in human antibodies to factor VIII.

Preparation and Characterization of NH2-Terminal Fibrinogen Bβ Fragments from N-DSK of Human Fibrinogen

1984 ◽  
Vol 51 (01) ◽  
pp. 016-021 ◽  
Author(s):  
S Birken ◽  
G Agosto ◽  
B Lahiri ◽  
R Canfield
Keyword(s):  
High Performance ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Reverse Phase ◽  
Human Fibrinogen ◽  
Human Volunteers ◽  
Cnbr Cleavage ◽  
Two Peaks

SummaryIn order to investigate the early release of NH2-terminal plasmic fragments from the Bβ chain of fibrinogen, substantial quantities of Bβ 1-42 and Bβ 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and Bβ 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. Bβ 1-42 and Bβ 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of Bβ 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.

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