Characterization Of The ADP-Induced Fibrinogen Btnd1Ng Sites On Human Platelets Using Photoaffinity Techniques: Some Preliminary Findings

1981 ◽  
Author(s):  
Ellinor I Peerschke ◽  
Mariorie B Zucker ◽  
Avner Rotman
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Membrane Fragment ◽  
Fibrinogen Receptor ◽  
Congenital Deficiency ◽  
Sds Page ◽  
Platelet Membrane Receptor

The interaction of fibrinogen with its, platelet membrane receptor was investigated using 125-labeled fibrinogen which was photoaffinity labeled with a light-sensitive azide. This photoreactive material (125I-NPA-fibr) was indistinguishable from unlabeled fibrinogen as well as from iodinated fibrinogen on SDS-PAGE. It bound specifically to platelets stimulated with ADP and was crosslinked to the platelet membrane after exposure to light ( λ >300 nm) for 4 min. No crosslinking was observed in the presence of EDTA or with platelets that failed to aggregate with ADP either due to the congenital deficiency thrombasthenia or following incubation with EDTA for 8 min at 37° , pH 7.8 and recalcification. SDS-PAGE of platelets bearing crosslinked 125I-NPA-fibr revealed a radiolabeled band of about 450,000 daltons in addition to the 340,000 dalton radioactive band of fibrinogen, suggesting that fibrinogen had been covalently bound to a platelet membrane component with an intact apparent molecular weight of approximately 110,000 daltons. Following reduction, an extra radioactive band was noted at 80,000 daltons. As the A∝-chains of fibrinogen were too weakly labeled to be detected by autoradiography, this indicated that either the Bβ or γchain of fibrinogen was attached to a 25,000-35,000 molecular weight platelet membrane fragment. We conclude that the additional radioactive bands observed after electrophoresis of platelets bearing specifically bound-photoaffinity labeled 125I-fibrinogen most likely represent the binding of the B β or γ chains of fibrinogen to the platelet fibrinogen receptor which may be GPIIb.

scholarly journals Characterization of the purified Chlamydomonas minus agglutinin.

1985 ◽  
Vol 101 (3) ◽  
pp. 1144-1152 ◽  
Author(s):  
P Collin-Osdoby ◽  
W S Adair
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Agarose Beads ◽  
Sds Page ◽  
Sexual Agglutinins ◽  
Molecular Morphology ◽  
High Degree

Chlamydomonas flagellar sexual agglutinins are responsible for the adhesion of opposite mating-type (plus and minus) gametes during the first stages of mating. Purification and partial characterization of the plus agglutinin was previously reported (Adair, W. S., C. J. Hwang, and U. W. Goodenough, 1983, Cell, 33:183-193). Here we characterize the purified minus molecule. We show it to be a high molecular weight, hydroxyproline-rich glycoprotein that migrates in the 3% stacking region of an SDS-polyacrylamide gel and is absent from two nonagglutinating minus mutants. Plus and minus agglutinins are remarkably similar, although nonidentical, in amino acid composition, molecular morphology, and reactivity in vivo and in vitro with monoclonal antibodies raised against the plus agglutinin. Moreover, the adhesiveness of both plus and minus agglutinins, when coupled to agarose beads, is abolished by thermolysin, trypsin, periodate, alkaline borohydride, reducing agents, or heat, but unaffected by exo- or endoglycosidases. The minus agglutinin, however, migrates just ahead of the plus molecule on SDS PAGE, is excluded from an anion-exchange (Mono Q) column, elutes earlier during hydrophobic interaction (Bio-gel TSK Phenyl 5PW) chromatography, and is sensitive to chymotrypsin digestion (unlike the plus agglutinin); therefore, it differs from the plus agglutinin in apparent molecular weight, net charge, relative hydrophobicity and proteolytic susceptibility. Nevertheless, our results generally demonstrate a high degree of homology between these complementary cell-cell recognition/adhesion molecules, which suggests that they are specified by genes that have a common evolutionary origin.

Characterization of a Form of Bovine Factor VIII Which Does Not Aggregate Human Platelets

1981 ◽  
Vol 46 (02) ◽  
pp. 479-484 ◽  
Author(s):  
Edward P Kirby
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Apparent Molecular Weight ◽  
Human Platelets ◽  
Procoagulant Activity ◽  
Rabbit Antibody ◽  
Factor Viii Related Antigen ◽  
Agarose Electrophoresis ◽  
Bovine Factor

SummaryFractionation of partially purified bovine factor VIII on tricalcium citrate columns produces a material which contains high levels of factor VIII procoagulant activity and factor VIII- related antigen, but does not aggregate human platelets. The procoagulant activity can be blocked by human inhibitors of factor VIII: C and by rabbit antibody to bovine factor VIII. Its activity can be increased by thrombin modification. The apparent molecular weight of this form of factor VIII is significantly lower than that of the forms of factor VIII which contain platelet aggregating activity, and it exhibits a higher mobility on agarose electrophoresis.

DEMONSTRATION OF SINGLE CHAIN UROKINASE-TYPE PLASMINOGEN ACTIVATOR (scu-PA) ON HUMAN PLATELET MEMBRANES

1987 ◽  
Author(s):  
S Park ◽  
L A Harker ◽  
E G Levin
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Single Chain ◽  
Plate Method ◽  
Platelet Membranes ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Sds Page

A role for platelets in enhancing fibrinolysis has been suggested. To elucidate the nature of fibrinolysis-accelerating effect of human platelets, different fractions of the platelets were tested for fibrinolytic activity by the fibr:i.n plate method in the presence of plasminogen and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by fibrin autography. The platelets were washed in Tyrode’s buffer containing 0.5 ug/ml prostaglandin Ef, 1 mM ethylenediaminetetraacetic acid (EDTA), and 1 mM phenylmethylsulfonyl fluoride by albumin density gradient separation and gel filtration techniques. Platelet membranes were isolated by differential centrifugation after disruption of the platelets by ultrasonication. The sedimented platelet membranes demonstrated plasminogen activation with subsequent fibrinolysis which was completely abolished in the presence of affinity-purified antibody to high molecular weight urokinase-type plasminogen activator (u-PA). Minimal u-PA activity was observed associated with the supernatant from sonicated platelets indicating that most of the detectable u-PA was membrane-bound. Fibrin autography following SDS-PAGE of the platelet membrane fraction revealed a lysis zone at the molecular weight level of 54,000. Single chain nature of the u-PA was demonstrated by immunoblot analysis of the platelet membrane after SDS-PAGE under reducing conditions. Treatment of the platelets with 1.2 u/ml alpha-thrombin eliminated membrane-associated u-PA activity and probably resulted from the cleavage and inactivation of scu-PA. u-PA activity was quantitated by the 125I_fibrin plate method: values in the range of 0.15-0.25 mU/109 platelets were observed. Most of the activity was liberated from the platelet membrane by exposure to 3 M KC1 or 0.1 M glycine, pH 2.3, but not to 10 mM EDTA. We conclude that human platelets have scu-PA on their membranes that may play a role as a carrier of scu-PA in blood circulation. Binding studies are in progress.

Partial characterization of cheese-ripening proteinases produced by the yeastKluyveromyces lactis

1983 ◽  
Vol 50 (4) ◽  
pp. 469-480 ◽  
Author(s):  
Paul A. Grieve ◽  
Barry J. Kitchen ◽  
John R. Dulley ◽  
John Bartley
Keyword(s):  
Molecular Weight ◽  
Kluyveromyces Lactis ◽  
Apparent Molecular Weight ◽  
Aminopeptidase Activity ◽  
Carboxypeptidase Y ◽  
Casein Hydrolysis ◽  
Cheese Ripening ◽  
Caseinolytic Activity ◽  
Proteinase A

SUMMARYAn extract ofKluyveromyces lactis416 and a β-galactosidase preparation (Maxilact 40000) contaminated with proteinase, showed similar pH profiles of caseinolytic activity. Similar modes of casein hydrolysis (κ-, > αs-, ≥ β-) were observed at pH 5·0 (the pH of Cheddar cheese), without detection of bitterness. The contaminated Maxilact preparation contained similar proteinase types to those detected in an autolysate ofK. lactis. Both the autolysate and the Maxilact preparation contained acid endopeptidase (proteinase A), serine endopeptidase (proteinase B) and serine exopeptidase (carboxypeptidase Y) activities. Some aminopeptidase activity was also detected in both preparations. There were some differences in apparent molecular weight and charge properties between proteinase A and B and carboxypeptidase Y from the 2 proteinase sources.

scholarly journals Immunohistochemical and immunochemical characterization of a new endothelial cell-specific antigen.

1986 ◽  
Vol 34 (2) ◽  
pp. 209-214 ◽  
Author(s):  
J U Alles ◽  
K Bosslet
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Specific Antigen ◽  
Similar Molecular Weight ◽  
Immunochemical Characterization ◽  
Sds Page

A new monoclonal antibody (moab BW 200) of IgG3 kappa-isotype was generated which recognizes an epitope located on an antigen molecule restricted to human neoplastic and non-neoplastic endothelial cells. The molecular weight of the antigen was determined using immunoprecipitation analysis followed by SDS-PAGE. Despite its similar molecular weight to FVIII-RAG, the antigen detected by moab BW 200 was shown to be different from FVIII-RAG.

An integral membrane protein antigen associated with the membrane attachment sites of actin microfilaments is identified as an integrin beta-chain

1988 ◽  
Vol 8 (2) ◽  
pp. 564-570
Author(s):  
P A Maher ◽  
S J Singer
Keyword(s):  
Molecular Weight ◽  
Membrane Protein ◽  
Protein Complex ◽  
Apparent Molecular Weight ◽  
Integral Membrane Protein ◽  
Beta Chain ◽  
Attachment Sites ◽  
Wide Range ◽  
Membrane Attachment

A monoclonal antibody (MAb 30B6) was recently described by Rogalski and Singer (J. Cell Biol. 101:785-801, 1985) which identified an integral membrane glycoprotein of chicken cells that was associated with a wide variety of sites of actin microfilament attachments to membranes. In this report, we present a further characterization of this integral protein. An immunochemical comparison was made of MAb 30B6 binding properties with those of two other MAbs, JG9 and JG22, which identify a component of a membrane protein complex that interacts with extracellular matrix proteins including fibronectin. We showed that the 110-kilodalton protein recognized by MAb 30B6 in extracts of chicken gizzard smooth muscle is identical, or closely related, to the protein that reacts with MAbs JG9 and JG22. These 110-kilodalton proteins are also structurally closely similar, if not identical, to one another as demonstrated by 125I-tryptic peptide maps. However, competition experiments showed that MAb 30B6 recognizes a different epitope from those recognized by MAbs JG9 and JG22. In addition, the 30B6 antigen is part of a complex that can be isolated on fibronectin columns. These results together establish that the 30B6 antigen is the same as, or closely similar to, the beta-chain of the protein complex named integrin, which is the complex on chicken fibroblast membranes that binds fibronectin. Although the 30B6 antigen is present in a wide range of tissues, its apparent molecular weight on gels varies in different tissues. These differences in apparent molecular weight are due, in large part, to differences in glycosylation.

Isolation and Characterization of Human Platelet β-Thromboglobulin

1975 ◽  
Author(s):  
D. S. Pepper ◽  
S. Moore ◽  
J. D. Cash
Keyword(s):  
Molecular Weight ◽  
Plasma Proteins ◽  
Human Platelet ◽  
Weight Fraction ◽  
Human Platelets ◽  
Low Molecular Weight ◽  
Purification Procedure ◽  
Isolation And Characterization

The thrombin released products from washed human platelets were separated by filtration on 4% agarose in 0.15 M NaCl. The high molecular weight PF4 complex was dissociated and re-chromatographed in 0.75 M NaCl. The low molecular weight fraction, including β thromboglobulin and a low MW anti-heparin was freed of plasminogen anti-activator by dissociation and chromatography in pH 3.5 pyridine acetic acid. The anti-activator was irreversibly denatured and albumin was removed in the void volume of the column. A more suitable purification procedure for recovery of all activities was affinity chromatography on heparin-agarose. The anti-activator was excluded and could be obtained free of plasma proteins by Sephadex G-200 chromatography. The βTG eluted at 0.3 M NaCl and the low MW anti-heparin at 1.5 M NaCl. The pure βTG (MW 36,000) was injected into rabbits and the resulting antiserum used to produce a radioimmunoassay for the release reaction in vivo.

A PLASMINOGEN ACTIVATOR INHIBITOR (PAI-2) CIRCULATES IN TWO HIGH MOLECULAR WEIGHT FORMS IN PREGNANCY

1987 ◽  
Author(s):  
N A Booth ◽  
A Reith ◽  
B Bennett
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Plasminogen Activator ◽  
Apparent Molecular Weight ◽  
Late Pregnancy ◽  
Plasminogen Activator Inhibitor ◽  
Molecular Weights ◽  
Histiocytic Cell ◽  
Sds Page ◽  
Pai 1

Normal vascular endothelium and platelet α-granules contain an inhibitor of plasminogen activator (PAI-1) of about 48000 molecular weight, which is released by stimuli such as thrombin. An immunologically distinct inhibitor (PAI-2) of about 47000 molecular weight has been purified from placenta and from a histiocytic cell line U-937. The level of PA-inhibition in plasma is raised in late pregnancy and this may be due to increases in PAI-1 or in PAI-2 or in both.Using SDS-PAGE and zymography on fibrin/plasminogen /u-PA detector gels, we have found that normal plasma contains a band of inhibition of apparent molecular weight 40000, which can be neutralised by antiserum raised against PAI-1. Pregnancy plasma contained this band as well as additional inhibitor bands of apparent molecular weights 75000 and 130000. The novel high molecular weight PA-inhibitors were detectable by zymography at about 12 weeks gestation. They were specific for plasminogen activator and did not inhibit plasmin. They were inhibited by antiserum raised against PAI-2 from U-937 cells (a gift from Dr EKO Kruithof) and thus are immunologically related to PAI-2. They may represent circulating complexes of PAI-2 with another protein or aggregates of PAI-2, which retain inhibitory activity after SDS-PAGE. PAI-2 appears to represent a pregnancy associated protein that circulates in a number of different molecular weight forms.

Localization and Functional Characterization of Three Thylakoid Membrane Polypeptides of the Molecular Weight 66000

1977 ◽  
Vol 32 (9-10) ◽  
pp. 817-827 ◽  
Author(s):  
Friederike Koenig ◽  
Wilhelm Menke ◽  
Alfons Radunz ◽  
Georg H. Schmid
Keyword(s):  
Molecular Weight ◽  
Electron Transport ◽  
Outer Surface ◽  
Thylakoid Membrane ◽  
Functional Characterization ◽  
Apparent Molecular Weight ◽  
Photochemical Reactions ◽  
Antigenic Determinants ◽  
Reaction Centre

Abstract Three polypeptide fractions with the apparent molecular weight 66 000 were isolated from stroma-freed Antirrhinum chloroplasts which were solubilized with dodecyl sulfate. Antisera to these fractions affect electron transport in distinctly different ways. For the characterization of the three antisera photochemical reactions of chloroplast preparations with artificial electron donors and acceptors as well the analysis of fluorescence rise curves were used. Antiserum 66 000 PSI-96 inhibits electron transport apparently on the acceptor side of photosystem I, provided the antibodies are adsorbed onto the outer surface of the thylakoid membrane. Antiserum 66 000 PSI-88 probably acts directly on the reaction centre I or on its immediate vicinity, if the antibodies are adsorbed at the inner surface of the thylakoid membrane. Antiserum 66 000 PSII-42 inhibits electron trans­ port in the region of photosystem II. The antigen towards which the antiserum is directed appears to belong to the reaction centre II, as also in the condition of high inhibition degrees, the fluorescence intensity remains unchanged. The antigenic determinants are located at the outer surface of the thylakoid membrane.

Isolation and Partial Characterization of Equine Antithrombin III.

1979 ◽  
Author(s):  
D.W. Estry ◽  
T.G. Bell ◽  
G.H. Tishkoff ◽  
J.C. Mattson ◽  
S.C. Estry
Keyword(s):  
Molecular Weight ◽  
Antithrombin Iii ◽  
Stable Complex ◽  
Sds Page ◽  
At Iii ◽  
Human Thrombin ◽  
Horse Plasma ◽  
Stoichiometric Complex

A protein analogous to human antithrombin III was isolated from fresh horse plasma. The procedure for purification was a modification of Thaler and Schmer’s two-step isolation procedure. The horse protein was homogeneous on 7.5% SDS-PAGE gels and had a molecular weight of 62,000 to 64,000 daltons in both reducing and non-reducing systems (human; 62,300). Rabbit anti-human antithrombin III was used to demonstrate a line of partial identity by Immunoelectrophoresis between the horse and human protein. The horse protein rapidly neutralizes human thrombin (34,000 daltons) and the reaction appears to be greatly potentiated by heparin. In order to establish the formation of 1:1 covalent stoichiometric complex between horse AT III and thrombin (IIa), time studies were run in the presence and absence of heparin. AT III (62,000) at 15 seconds, 2, 5, 10 and 60 minutes formed a stable complex with thrombin (32,000) having a molecular weight of 86,000 daltons. Additional bands developing with time are due to the autolytic capabilities of the uncomplexed IIa. The major autolytic band had a molecular weight of 70,000 daltons. Addition of heparin potentiated the interaction although it did not change the stoichio-metry of the complexes formed. The data accumulated to date demonstrates the similarities between the human and horse protein and the possibilities of using the horse as a model system for the evaluation of AT III replacement therapy in vivo.

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