Search results for "Molecular-Weight"
showing 10 items of 72 documents
Multiple voltage‐gradient gel electrophoresis system
2001
A new device, based on the principle of voltage-gradient gel electrophoresis, was developed in order to enhance differentiation of the distance across the range of molecular masses in the electrophoretic fractionation of nucleic acids in an agarose matrix. The apparatus has a series of modular parallel plates, placed slantwise to allow reiteration of the voltage gradient effect along the gel. This subjects DNA fragments of variable length to differential runnings according to their original position in the gel. Both the number of slantwise plates and the distance between them can be changed to modify operating performance. Our system allows better fractionations as compared to conventional …
Determination of molecular weights and Stokes' radii of non-denatured proteins by polyacrylamide gradient gel electrophoresis. 2. Determination of th…
1982
Under certain conditions in polyacrylamide gradient gel electrophoresis (PAGGE), a linear correlation between the logarithm of the size of calibration proteins (log MW or log Rs) and the square root of their migration distance (√D) can be observed; slope and intercept of the calibration curve depend on the duration of electrophoresis; linearity, however, is maintained over a wide range (4-60 h, 200 V) (Rothe and Purkhanbaba, Electrophoresis 1982, 3, 33–42.) Using this method the reaction of plant isozyme systems penetrating a linear polyacrylamide (PAA) gradient gel was investigated: lactate dehydrogenase (LDH) from potato tubers behaves similarly to animal calibration proteins. The enzyme …
Determination of molecular weights and Stokes' radii of non-denatured proteins by polyacrylamide gradient gel electrophoresis 3. Estimation of the up…
1985
Studying the separation behavior of various native carbonic anhydrase isozymes from mammalian erythrocytes we found that the migration of these enzymes differs from that of the marker proteins commonly used in gradient gel electrophoresis. In alkaline buffer systems the enzymes from human, bovine, rabbit, and canine erythrocytes start to migrate with a size apparently 6 to 12 times larger than their monomeric size, then gradually lose in apparent size and finally end up in a size equivalent to their monomeric mol mass. We determined the monomeric mol mass of the various carbonic anhydrase forms to be 23 000 to 39 000 (g/mol). These values are in accordance with different data in the literat…
Prothrombinase-Induced Clotting Time Assay for Determination of the Anticoagulant Effects of Unfractionated and Low-Molecular-Weight Heparins, Fondap…
2008
The prothrombinase-induced clotting time assay (PiCT, Pentapharm, Basel, Switzerland) is a clotting assay sensitive to factor Xa and factor IIa inhibitors. It is based on the addition of factor Xa and snake venom RVV-V (Russell viper venom factor V activator) specifically activating factor V and phospholipids to platelet-poor plasma. Following an incubation time, the mixture is recalcified and the clotting time is determined. An almost linear dose-response and high sensitivity of the assay for unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), r-hirudin, and argatroban was found. Fondaparinux showed a nonlinear dose-response. By using ex vivo samples, the following Pearson…
Mapping the cell binding site on high molecular weight kininogen domain 5.
1995
Investigations mapped the region(s) on the light chain of high molecular weight kininogen (HK) that participates in cell binding. Sequential and overlapping peptides of domain 5 (D5H) were synthesized to determine its cell binding site(s). Three peptides from non-overlapping regions on D5H were found to inhibit biotin-HK binding to endothelial cells. Peptides GKE19 and HNL 21 weakly inhibited biotin-HK binding with IC50 of 792 and 215 microM, respectively. Peptide HKH20 inhibited biotin-HK binding with an IC50 of 0.2 microM. Two peptides, GGH18 and HVL24, which overlapped HKH20, also inhibited biotin-HK binding to endothelial cells with IC50 values of 108 and 0.8 microM, respectively. Bioti…
Mapping of the high molecular weight kininogen binding site of prekallikrein. Evidence for a discontinuous epitope formed by distinct segments of the…
1993
Prekallikrein, a glycoprotein involved in contact phase activation, circulates in plasma in the form of a binary complex with high molecular weight kininogen (H-kininogen). The binding to H-kininogen is mediated by the prekallikrein heavy chain consisting of four repetitive domains, A1-A4. To define more precisely the region(s) involved in kininogen binding, we have employed an affinity cross-linking strategy with a synthetic peptide of 31 residues which mimics the prekallikrein binding site of H-kininogen. Cross-linking of the radiolabeled peptide to (pre)kallikrein revealed a binding segment in the NH2-terminal portion of the prekallikrein heavy chain; another binding segment was located …
Mapping of the Discontinuous H-kininogen Binding Site of Plasma Prekallikrein
1999
Plasma prekallikrein, a zymogen of the contact phase system, circulates in plasma as heterodimeric complex with H-kininogen. The binding is mediated by the prekallikrein heavy chain consisting of four apple domains, A1 to A4, to which H-kininogen binds with high specificity and affinity (K(D) = 1.2 x 10(-8) M). Previous work had demonstrated that a discontinuous kininogen-binding site is formed by a proximal part located in A1, a distal part exposed by A4, and other yet unidentified portion(s) of the kallikrein heavy chain. To detect relevant binding segment(s) we recombinantly expressed single apple domains and found a rank order of binding affinity for kininogen of A2 > A4 approximately A…
Human kininogens interact with M protein, a bacterial surface protein and virulence determinant.
1995
Streptococcus pyogenes, the most significant streptococcal species in clinical medicine, expresses surface proteins with affinity for several human plasma proteins. Here we report that kininogens, the precursors to the vasoactive kinins, bind to the surface of S. pyogenes. M protein, a surface molecule and a major virulence factor-in these bacteria, occurs in > 80 different serotypes. Among 49 strains of S. pyogenes, all of different M serotypes, 41 bound radiolabelled kininogens, whereas 6 M protein-negative mutant strains showed no affinity. M protein of most serotypes bind fibrinogen, and among the 55 strains tested, binding of kininogens was closely correlated to fibrinogen bindi…
Gadolinium-chelating nanogels as MR contrast agesnts specifically targeting tumor cells
2014
Development of multifunctional nanogels coordinating paramagnetic ions and displacing targeting ligands for preferential accumulation into tumors. Low molecular-weight Gd-chelates are widely used in clinical MRI for various purposes. However, these contrast agents (CAs) have several shortcomings: they rapidly extravasate from blood vessels to the interstitial space, have a short circulation times and show poor contrast at high magnetic fields. Incorporating gadolinium into flexible nanogels has the potential of increasing intravascular half-life, accumulation and retention in specific body compartments of the CA as well as increasing the MR signal, since many metal ions can be coordinated t…
Multifunctional Poly(ethylene glycol)s
2011
In the rapidly evolving multidisciplinary field of polymer therapeutics, tailored polymer structures represent the key constituent to explore and harvest the potential of bioactive macromolecular hybrid structures. In light of the recent developments for anticancer drug conjugates, multifunctional polymers are becoming ever more relevant as drug carriers. However, the potentially best suited polymer, poly(ethylene glycol) (PEG), is unfavorable owing to its limited functionality. Therefore, multifunctional linear copolymers (mf-PEGs) based on ethylene oxide (EO) and appropriate epoxide comonomers are attracting increased attention. Precisely engineered via living anionic polymerization and d…