Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02749 (beta2-glycoprotein I)
 836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anions with strong electro-negative charges, like sulphuric esters of polysaccharides (heparin, dextran sulphate M.W. 15 00), the sodium salt of polyanethol sulfonic acid (liquoid, Roche), anionic detergents (sodium dodecylsulphate, sodium oleate, sodium deoxycholate), and the sodium salt of phosphotungstic acid were added to human serum or citrated plasma. For each compound several final concentrations were adopted, the highest being 4%. By using microimmunoelectrophoresis and numerous specific antisera against human plasma proteins, it was demonstrated that at pH 8.60 anions increase electrophoretic mobility of the following antigens: lipoproteins alpha and beta; fibrinogen; beta 2-glycoprotein I; beta 2-glycoprotein II ; antithrombin III. All reagents utilized do not react with all these proteins; for instance, only detergents accelerate the migration rate of a lipoproteins. Besides, depending on the protein, this or that reagent may be the most active. Thus, in the polysulphate group, heparin has the highest affinity for antithrombin III, liquoid for fibrinogen and dextran sulphate for beta 2-glycoprotein I.
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PMID:[Polysulfates, anionic detergents, sodium phosphotungstate and electrophoretic mobility of plasmatic proteins]. 67 30

Inositolphospholipid-accelerated activation of prekallikrein by alpha-factor XIIa was determined by measuring the appearance of kallikrein amidolytic activity towards the chromogenic substrate, D-prolyl-phenylalanyl-arginyl p-nitroanilide (S-2302). The activation reaction did not exhibit normal Michaelis-Menten kinetics. The Hill coefficient was found to be 1.6 indicating that the activation followed an allosteric reaction mechanism. The temperature dependence of the reaction showed a thermal transition at 30 degrees C, which in addition to the allosteric reaction mechanism is indicative of a conformational change of prekallikrein following binding to the inositolphospholipid. The reaction exhibited pH optimum at pH 7.2 and ionic strength optimum at 50 mM NaCl. At optimal conditions the apparent KA value and the kcat/KA value for factor XIIa on prekallikrein were calculated to be 73 nM and 9.3 x 10(6) s-1 M-1, respectively. Kinetic constants could not be calculated at salt concentrations higher than the optimal concentrations, as Lineweaver-Burk plots were curvilinear in agreement with the Hill coefficient greater than unity. The activation was inhibited competitively by beta 2-glycoprotein I with a Ki value of 77 nM as determined by the Dixon plot.
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PMID:Inositolphospholipid-accelerated activation of prekallikrein by activated factor XII and its inhibition by beta 2-glycoprotein I. 284 32