scholarly journals Studies on human pregnancy-associated plasma protein A. Purification by affinity chromatography and structural comparisons with α2-macroglobulin

1980 ◽  
Vol 191 (3) ◽  
pp. 799-809 ◽  
Author(s):  
R G Sutcliffe ◽  
B M Kukulska-Langlands ◽  
J R Coggins ◽  
J B Hunter ◽  
C H Gore
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Plasma Protein ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein A ◽  
Carbohydrate Content ◽  
Polyacrylamide Gel ◽  
Gel Chromatography ◽  
Tryptic Fragment

Pregnancy-associated plasma protein-A (PAPP-A) has been purified by a combination of methods including antibody-affinity chromatography. The resultant protein, obtained in 16% yield from maternal serum, appeared as a single major component on non-denaturing polyacrylamide and SDS/polyacrylamide gel electrophoresis. The protein showed a single component when analysed by isoelectric focusing under denaturing conditions in the presence and absence of reduction and had a pI of 4.34 and 4.42 respectively. These pI values were indistinguishable from those of alpha 2-macroglobulin (alpha 2M). The molecular weight of the PAPP-A polypeptide as shown by SDS/polyacrylamide-gel electrophoresis was 187000, with a minor component of mol.wt. 82500 that was attributed to proteolysis. Since native PAPP-A had a molecular weight on gel chromatography very similar to that of alpha 2M (620000–820000), it was concluded that PAPP-A was a homotetramer. In the absence of reduction, a high-molecular-weight (420000) protomer of PAPP-A was found. It was deduced that PAPP-A, like alpha 2M, is a dinner, whose protomers are composed of disulphide-linked polypeptide chains. It was found that the molecular weight of the PAPP-A polypeptide exceeded that of alpha 2M by 3.3%, but that the total carbohydrate content of PAPP-A exceeded that of alpha 2M by 10% and that its neutral carbohydrate content exceeded that of alpha 2M by between 7.4 and 9.0%. The significance of the estimated molecular weights of alpha 2M (181000) and its major tryptic fragments is discussed in the light of published values. A tryptic fragment alpha 2M (82500 mol.wt.) was apparently the same size as the major tryptic fragment of PAPP-A.

Purification and partial characterization of cysteine-glutamate transaminase from rat liver

1977 ◽  
Vol 55 (9) ◽  
pp. 958-964 ◽  
Author(s):  
M. P. C. Ip ◽  
R. J. Thibert ◽  
D. E. Schmidt Jr.
Keyword(s):  
Molecular Weight ◽  
Rat Liver ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Liver Homogenate ◽  
Polyacrylamide Gel ◽  
Gel Chromatography ◽  
Labile Hydrogen ◽  
Apparent Homogeneity

Cysteine-glutamate transaminase (cysteine aminotransferase; EC 2.6.1.3) has been purified 149-fold to an apparent homogeneity giving a specific activity of 2.09 IU per milligram of protein with an overall yield of 15%. The isolation procedures involve the preliminary separation of a crude rat liver homogenate which was submitted sequentially to ammonium sulfate fractionation, TEAE-cellulose column chromatography, ultrafiltration, and isoelectrofocusing. The final product was homogenous when examined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). A minimal molecular weight of 83 500 was determined by Sephadex gel chromatography. The molecular weight as estimated by polyacrylamide gel electrophoresis in the presence of SDS was 84 000. The purified enzyme exhibited a pH optimum at 8.2 with cysteine and α-ketoglutarate as substrates. The enzyme is inactivated slowly when kept frozen and is completely inactivated if left at room temperature for 1 h. The enzyme does not catalyze the transamination of α-methyl-DL-cysteine, which, when present to a final concentration of 10 mM, exhibits a 23.2% inhibition of transamination of 30 mM of cysteine. The mechanism apparently resembles that of aspartate-glutamate transaminase (EC 2.6.1.1) in which the presence of a labile hydrogen on the alpha-carbon in the substrate is one of the strict requirements.

CHARACTERIZATION OF HUMAN PLATELET ClQ BINDING SITES

1987 ◽  
Author(s):  
E IB PEERSCHKE ◽  
B Ghebrehiwet
Keyword(s):  
Molecular Weight ◽  
Binding Sites ◽  
Gel Electrophoresis ◽  
Phosphate Buffer ◽  
Specific Binding ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein A ◽  
Inhibitory Effect ◽  
Polyacrylamide Gel ◽  
Triton X

We have recently shown that platelets possess specific binding sites for Clq, a subcomponent of the first component of complement, Cl, and that occupancy of these receptor sites correlates with the previously described inhibitory effect of Clq on collagen-induced platelet aggregation. To further characterize platelet Clq receptors, washed platelets were solubilized in 5 mM sodium phosphate buffer, pH 7.5 containing 10 mM EDTA, 150 mM NaCl, 10 mM EACA, 0.5 mM PMSF, and 1% Triton X-100. After dialysis against 5 mM phosphate buffer pH 7.5 containing 10 mM EDTA, 20 mM NaCl, 10 mM EACA,0.5 mM PMSF and 0.1% Triton X-100, the lysate was passed over Clq-Sepharose-4B affinity columns. A single protein peak eluted with buffer containing 300 mM NaCl. This peak was composed of two predominant molecular weight species (85-95K, 60-66K) as assessed by SDS-polyacrylamide gel electrophoresis under non-reducing conditions. When 125-iodine surface labeled platelets were solubilized and applied to Clq-Sepharose affinity resins, the same two molecular weight species eluted and could be visualized by autoradiography following SDS-polyacrylamide gel electrophoresis. Immunoabsorption studies performed under nondenaturing conditions using protein A and the IIl/Dl monoclonal antibody, which binds specifically to platelets and inhibits platelet-Clq interactions, revealed that the 85-95K molecular weight component was preferentially absorbed, but incomplete immunoabsorption of the 60-66K molecular weight constituent was also noted. Affinity purified Clq binding sites sedimented as a single peak during 5-40% sucrose density ultracentrifugation with an S value of approximately 2.4. In addition, both the 85-95K and the 60-66K molecular weight species coeluted in the void volume of Sephadex G-100 columns. The data suggest that the 85-95K and 60-66K molecular weight species represent platelet membrane Clq binding sites, and that these sites may form weak, noncovalently associated complexes.

Purification Of Factors IX And X From Clinical Concentrate

1981 ◽  
Author(s):  
G C Russell ◽  
G Kemble ◽  
E G D Tuddenham
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Deae Cellulose ◽  
Polyacrylamide Gel ◽  
Single Band ◽  
Factor Ix ◽  
Factor X ◽  
Clinical Factor

Human factors IX and X have been purified to homogeneity from clinical factor IX concentrate that had been rejected for therapeutic use due to particulate contamination. (It was necessary to start with this material since in the UK, plasma is not commercially available). The procedure involved barium citrate adsorption followed by ammonium sulphate elution, DEAE- cellulose chromatography, gel filtration on Sephacryl S-200 and affinity chromatography on heparin sepharose gel. The preparation of factor IX at this stage showed a single band on SDS-polyacrylamide gel electrophoresis, of molecular weight 58,000. No change in molecular weight was observed in the presence of 2-mercaptoethanol. A further affinity chromatography column - poly (homoarginine) Sepharose or dextran sulphate sepharose - was necessary to obtain homogeneous factor X. The preparation obtained showed a single band on SDS-polyacrylamide gel electrophoresis of molecular weight 67,000. In the presence of 2-mercaptoethanol, two bands were obtained of molecular weights 49000 and 17000 representing the heavy and light chains respectively of factor X. The purified coagulation proteins contained no activated species detectable by nonactivated partial thromboplastin time or by chromogenic substrate (S2222) assay. Prothrombin protein Sand protein C are by-products of this purification procedure.

scholarly journals Proteoglycans of bovine periodontal ligament and skin. Occurrence of different hybrid-sulphated galactosaminoglycans in distinct proteoglycans

1982 ◽  
Vol 201 (1) ◽  
pp. 27-37 ◽  
Author(s):  
C H Pearson ◽  
G J Gibson
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Periodontal Ligament ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Sedimentation Equilibrium ◽  
Gel Chromatography ◽  
Dermatan Sulphate ◽  
Self Association

A proteoglycan purified from 4 M-guanidinium chloride extracts of bovine periodontal ligament closely resembled that of bovine skin, except for a rather lower protein content and a higher molecular weight (120 000 compared with about 90 000) by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The latter difference was explained by the molecular weights (29 000 and 16 000) of the respective dermatan sulphate components, each of which was rich in L-iduronate (about 75% of the total hexuronate). Significant amounts of other glycosaminoglycans did not occur in these proteoglycans, which were homogenous on gel chromatography and agarose/polyacrylamide-gel electrophoresis. Polydispersity was observed in sedimentation equilibrium experiments, but proteolysis or self-association of the proteodermatan sulphates may have affected these results. Ligament proteoglycans that were almost completely extracted with 0.1 M-NaCl contained less protein of a completely different amino acid composition than the proteodermatan sulphates. They were heterogeneous in size but generally smaller than cartilage proteoglycans and L-iduronate was a component, comprising about 7% of the total hexuronate of the sulphated galactosaminoglycan chains. The latter consisted of two fractions differing in molecular weight, but a dermatan sulphate with a high L-iduronate content was not present. These proteoglycans had some resemblance to D-glucuronate-rich proteoglycans of other non-cartilaginous tissues. Such compounds, however, are difficult to categorize at present.

Prothrombin Metz : Purification and Characterization of a Variant of Human Prothrombin

1979 ◽  
Author(s):  
M Ribieto ◽  
J Elion ◽  
D Labie ◽  
F Josso
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Factor Xa ◽  
Polyacrylamide Gel ◽  
Cleavage Pattern ◽  
Purification And Characterization ◽  
Double Immunodiffusion ◽  
The Family

For the purification of the abnormal prothrombin (Pt Metz), advantage has been taken of the existence in the family of three siblings who, being double heterozygotes for Pt Metz and a hypoprothrombinemia, have no normal Pt. Purification procedures included barium citrate adsorption and chromatography on DEAE Sephadex as for normal Pt. As opposed to some other variants (Pt Barcelona and Madrid), Pt Metz elutes as a single symetrical peak. By SDS polyacrylamide gel electrophoresis, this material is homogeneous and appears to have the same molecular weight as normal Pt. Comigration of normal and abnormal Pt in the absence of SDS, shows a double band suggesting an abnormal charge for the variant. Pt Metz exhibits an identity reaction with the control by double immunodiffusion. Upon activation by factor Xa, Pt Metz can generate amydolytic activity on Bz-Phe-Val-Arg-pNa (S2160), but only a very low clotting activity. Clear abnormalities are observed in the cleavage pattern of Pt Metz when monitored by SDS gel electrophoresis. The main feature are the accumulation of prethrombin l (Pl) and the appearance of abnormal intermediates migrating faster than Pl.

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