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PubMed1977

Humic-like substances of bacterial origin. II. Fractionation of the bacterial humic-like substances by gel filtration on sephadex gels.

Humic-like substances obtained from cells of Pseudomonas acidovorans were separated on Sephadex G-25 into two groups of substances of different molecular weight. The substances of the molecular weight greater than 5000 were successively separated on Sephadex gels G-50, G-75, G-100. Five fractions of different molecular weight were obtained, the percentage of which varied depending on the media used and time of incubation of the bacteria. Most (38%--46%) of the compounds contained in the bacterial humic acids were of approximate molecular weight of 40 000--50 000. The distribution of the fractions in the bacterial "humic-acids" was compared with those of the humic acid made by Fluka A. G. The synthetic humic acid contained most (approximately 40%) of the compounds of approximate molecular weight of 8000--10 000. In the bacterial and synthetic material the content of the compounds with the molecular weight above 100 000 was very similar (8%--12%).

Chromatography, Gel↗
PubMed1998

Isolation of the factor VIII-von Willebrand factor complex directly from plasma by gel filtration.

A high capacity gel filtration system was developed with the purpose of isolating factor VIII (FVIII) and von Willebrand factor (vWF) directly from plasma in significantly higher yields than obtained by cryoprecipitation, the technique most commonly used to recover FVIII-vWF from human plasma. After laboratory-scale gel filtration of plasma, a FVIII-containing fraction was collected containing about 90% of FVIII in the applied plasma and with almost tenfold higher purity than that obtained by cryoprecipitation. The gel filtration step has been scaled up for use as the initial step in the manufacturing process for a FVIII preparation (Nordiate).

Chromatography, Gel↗
PubMed1987

Molecular weight standards for calibration of gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis: ferritin and apoferritin.

Ferritin and apoferritin are widely used for the calibration of gel filtration columns and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and are commercially offered for these purposes as part of molecular weight calibration kits. Many of the reported applications are severely in error as presented in leading references and application manuals. The manufacturers have based their recommendations on incorrect physicochemical parameters in the literature and incorrect or inadmissible assumptions about the protein subunit composition and architecture and have not taken into account the unusual resistance of these proteins to denaturation in SDS. Here the relevant physicochemical parameters of horse spleen apoferritin as reported in the literature are critically reevaluated and the best current estimates are identified as the following: weight average molecular weight of apoferritin, Mw = 481,200; molecular weight of subunits, major subunit, ML = 19,889; minor subunit, MH = 22,200; apparent specific volumes in 0.02 M acetate buffer, pH 5.5, and 0.1 M NaCl, phi = 0.721 ml g-1 and phi' = 0.743 ml g-1; partial specific volume at 20 degrees C, v = 0.738 ml g-1; viscosimetric molar volume, M[n] = 1.78 X 10(6) ml mol-1; Stokes radius, RSt = 67.1 A; viscosimetric radius, Rvis = 65.6 A; sedimentation coefficient S degrees 20, w = 16.6 S; translational diffusion coefficient, D20, w = 3.24 X 10(-7) cm2 s-1. Recommendations are provided for proper application of ferritin and apoferritin for calibration purposes in gel filtration and SDS-polyacrylamide gel electrophoresis.

Animals↗
PubMed1980

Determination of mulecular-weight distribution of aorta glycosaminoglycans by automated gel filtration.

This report describes an automated gel filtration procedure for estimation of molecular weights of glycosaminoglycans using Technicon sugar analyzer. A Sepharose CL-6B column was used for filtration. The method has been applied to determining the distribution of molecular weights of glycosaminoglycans from human aorta. The glycosaminoglycans were fractionated on a Dowex 1 (Cl-) column prior to gel filtration. On gel filtration, hyaluronic acid resolved into two components with estimated molecular weights of 38,000 and 8000. A molecular weight of 22,000 was estimated for heparan sulfate. Chondroitin 6-sulfate and dermatan sulfate eluted from the column in one peak, suggesting these two glycosaminoglycans have a similar molecular weight, 18,000. The procedure was found suitable for studying the gel filtration behavior of proteoglycans from bovine aorta and lung.

Animals↗
PubMed1966

Isolation and properties of the electrophoretic components of human growth hormone by Sephadex-gel filtration and preparative polyacrylamide-gel electrophoresis.

1. Human growth hormone was prepared from acetone-dried residues after extraction of gonadotrophins from pituitary glands. 2. Crude growth hormone was purified by gel filtration on Sephadex, resulting in a product that is soluble in water or 0.5% sodium chloride. It is painless on injection and shows a twofold increase in biological potency. Aggregation of growth hormone on Sephadex columns can be avoided by the addition of urea (6m) and EDTA (1mm) to the buffer. 3. Growth hormone appeared as a single component from Sephadex and ion-exchange columns and sedimented as a single boundary in the ultracentrifuge. In the circular disk electrophoresis, however, the growth hormone showed one faster and two slower-moving anionic components. 4. These components were isolated by preparative electrophoresis on polyacrylamide columns. The purified growth hormone and its three components sedimented as single boundaries with coefficients 2.62, 2.66, 2.66 and 2.83s respectively. 5. Amino acid analyses of the purified growth hormone and its components were closely related. End-group analysis of purified growth hormone and its components showed only phenylalanine at both N- and C-terminals. 6. The purified growth hormone and its components were essentially free of other pituitary hormones, but contained significant prolactin activity. The biochemical similarities among the electrophoretic components of human growth hormone and the presence of the same three components in the growth hormone prepared from a single human pituitary gland suggest polymorphism of a biologically active protein molecule.

Journal Article↗
PubMed1980

Validation of washing procedures for maintaining a microbiologically clean gel filtration column.

Chromatographic gel filtration matrixes used in various separation techniques are subject to microbial contamination. The need for a microbe-free column is critical when preparing materials that require a low or zero microbial count. This report proposes two alternative washing systems: 0.02 N HCl containing 0.81% NaCl, and 0.1 M tromethamine--hydrochloride buffer (pH 7.0) containing 0.81% NaCl and 0.02% thimerosal. These washing systems were validated using a 100 x 2.6-cm column packed with a modified dextran gel slurry previously inoculated with known counts of USP test organisms. After each wash, the column separation characteristics were verified further with appropriate test proteins.

Bacteria↗
PubMed1970

A study of calf thymus histone fraction F2(b) by gel filtration.

The gel-filtration behaviour of calf thymus histone fraction F2(b) was studied at three different salt concentrations (0.01m-, 0.10m- and 1.00m-sodium chloride) and two different pH ranges (pH3-4 and pH6.7-7.1). Other histone fractions [F1, F2(a) and F3] were also utilized to assist interpretation of the data. It was found that the Stokes radius of histone fraction F2(b) was not significantly changed when the salt concentration was increased, implying that the aggregation of the individual histone molecules (Edwards & Shooter, 1969) resulted in only relatively minor changes in the hydrodynamic volume. Aggregation would appear to be due to the salting out of hydrophobic regions giving rise, in the aggregate, to a compact core of hydrophobic groups from which protrude the remaining basic parts of the molecule. Repulsion between charged groups on the basic regions of individual histone molecules would give the aggregate approximately spherical symmetry, the diameter of the aggregate approximating to the length of a single histone molecule.

Animals↗
PubMed1987

[Molecular composition of the fractions of immunoglobulin preparations studied by gel filtration].

The method of gel filtration in columns permitted the separation of aggregated fractions into polymers whose content did not exceed 10% and dimers, their content ranging from 3.6% to 22.11%. The preparations were also found to contain fractions of monomers and fragments, Fab-fragments being detected in 10 out of 20 batches under study (4.04-27.36%). The shelf life of all preparations did not exceed 8-12 months. The use of spectrophotometric techniques ensured obtaining the most objective results in the calculation of the percentage of fractions contained in immunoglobulin preparations. The evaluation of the molecular composition of immunoglobulin preparations by the method of gel filtration is conducive to the improvement of their quality.

Chromatography, Gel↗
PubMed1978

[Isolation of sarcolemma acetylcholinesterase fractions by gel-filtration through Sepharose 2B].

Gel-filtration of 0,6 M NaCl and 0,6 M NaCl--0,1% Triton X-100 extracts of freshly isolated sarcolemma through Sepharose 2B (1,5 X 72 cm) has revealed one symmetric peak of acetylcholinesterase activity containing phospholipid and cholesterol, moving faster than fibrinogen and tyreoglobulin. The acetylcholinesterase fraction is substantially separated from other extract proteins. Gel-filtration of extracts from long-store, treated by ultrasound or high concentration of detergent sarcolemma has revealed some peaks of acetylcholinesterase activity, which may be suggested to be degraded forms of the complex high molecular weight structure. All species of acetylcholinesterase are converted by treatment with trypsin to a form moving upon gel-filtration with enzyme-marker catalase. The microsome extracts contain only the form moving with catalase.

Acetylcholinesterase↗
PubMed1969

Antigens of Neisseria gonorrhoeae: characterization by gel filtration, complement fixation, and agar-gel diffusion of antigens of gonococcal protoplasm.

With the use of the agar-gel-diffusion and complement-fixation techniques, it was shown that protoplasm from different gonococcal isolates reacted with sera from some humans with a history of gonorrhea but did not react with "normal" human sera. The reactive antigen(s) could be partially separated from the other antigens by passing the gonococcal protoplasm through Sephadex G-200. The antigen(s) reacting in the gel-diffusion and complement-fixation tests appeared in the same fraction. On the basis of Sephadex gel filtration, the molecular weight of this antigen(s) is probably greater than 200,000.

Animals↗
PubMed2005

Determining the subunit structure of phosphodiesterases using gel filtration and sucrose density gradient centrifugation.

Size-exclusion chromatography (gel filtration) is a widely used method to determine the molecular weight of a protein. Often, the elution volume of several standard proteins is plotted against their known molecular weight to generate a standard curve, which is then used to determine the molecular weight of the protein of interest by its elution volume. However, gel filtration does not measure the mass of a particle as such, but the Stokes radius (Rs), a property dependent on mass, shape, and hydration of a protein. Thus, this method works well only if the protein of interest has a spherical symmetrical shape and an average hydration level. For all other proteins, the use of gel filtration as the sole means to determine the molecular weight will be misleading. The molecular weight of any given protein can be calculated, however, using the method of Siegel and Monty. This method combines Stokes radii obtained from gel filtrations and sedimentation coefficients derived from density gradient centrifugations to calculate the mass of a protein independently of its shape or hydration. It has been shown previously that PDE4D3, a representative of the long PDE4 splice forms, behaves as a dimer, whereas PDE4D2, a prototype of the short PDE4 splice forms, is a monomer. Both proteins exhibit an anomalous behavior on gel filtration columns. For this reason, they are used in this study to demonstrate the necessity of performing both gel filtration and density gradient centrifugation to determine the molecular weight of a protein.

3',5'-Cyclic-AMP Phosphodiesterases↗