Search results for "molecular mass"

Electron microscopy and biochemical characterization of a 350-kDa annular hemolymph protein from the keyhole limpet Megathura crenulata

1994

The isolation and biochemical characterization of an annular non-hemocyanin hemolymph protein from a marine gastropod, the Californian giant keyhole limpet (Megathura crenulata) is presented. By analytical ultracentrifugation, the protein has a sedimentation coefficient of 12S and molecular mass of approximately 350 kDa. The subunit mass, obtained by SDS/PAGE in the presence of -SH reagent and 8 M urea, is approximately 35 kDa, thereby indicating the presence of 10 subunits in the native molecule. By negative staining, the protein is revealed in one predominant image projection as a pentagonal approximately 8 nm ring-like structure with an approximately 2-nm stain-filled centre and, in anot…

A strategy for chromatographic and structural analysis of monosaccharide species from glycoproteins.

1996

A general strategy for the chromatographic and structural analysis of the monosaccharide species fucose (Fuc), N-acetylgalactosamine (GalNAc), N-acetylglucosamine (GlcNAc), galactose (Gal), glucose (Glc), mannose (Man), N-acetylneuraminic acid (NANA) present in glycoproteins is described. Qualitative and quantitative aspects for the separation of these glycoprotein monosaccharides (monosaccharide species) using ligand-exchange chromatography (LEC) and high pH anion-exchange chromatography (HPAEC) in combination with pulsed-amperometric detection (PAD), refractive index (RI) and ultraviolet (UV) monitoring are discussed in detail. The conditions for the acidic hydrolysis of glycoproteins and…

Isolation, structural and toxicological characterization of three new mycotoxins produced by the fungusAureobasidium pullulans.

1993

3 substances, B1, B2, and E1 were isolated from culture medium extracts ofAureobasidium pullulans by reversed phase liquid chromatography and subsequent liquid chromatographic purification steps on silica gel.The 3 compounds inhibited the metabolism ofSaccharomyces cerevisiae and showed toxic effects in the growth inhibition test toEscherichia coli andBacillus subtilis.Elementary analysis and mass spectroscopical methods revealed sum formulas of C23H22O6, C22H20O6 and C24H28O3 for B1 B2, and E1 and molecular weights of 394, 380, and 364, respectively. Mass spectroscopical, UV-, IR-,(13)C-NMR, and(1)H-NMR-spectroscopical investigations revealed polycyclic, non-aromatic compounds containing s…

Separation studies of amino acids, proteins and enzymes on bonded 1,2-dihydroxy-, 1,2-hydroxylamino-and amino silica packings

1979

1,2-dihydroxy-3-propoxypropyl (HPPS), 1-amino-2-hydroxy-3-propoxypropyl (AHPS) and 1-aminoethyl-3-aminopropyl (AEAPS) silica were synthesized by means of both a surface modification procedure (I) and a bulk modification procedure (II). Method (I) gave a surface concentration, α, of functional groups of 2–3 μmole/m2, whereas method (II) gave values up to 5 μmole/m2. Retention times, peak asymmetries and plate heights of thiamine and ascorbic acid eluted with aqueous buffer solutions ranging from pH 5.3 to 9.2 gave only a±5% variation over periods of 12 hours and more. The recoveries of selected enzymes and proteines examined under static and dynamic conditions were between 60% and 100% depen…

Keyhole Limpet Hemocyanin (KLH): Slow In Vitro Reassociation of KLH1 and KLH2 from Immucothel®

1998

Abstract Following our in vitro reassociation of keyhole limpet hemocyanin subunits in the presence of high concentrations (100 mM each) of calcium and magnesium chloride (Harris et al., 1997a, Micron 28, 31–41; 1997b, Micron 28, 43–56), we have now extended our investigations by using a buffer system containing a lower concentration of the two divalent cations (10 mM each). Reassociation of mixed KLH subunits present in the commercially available product Immucothel® was performed using a standardized buffer solution containing 50 mM Tris–HCl, 150 mM NaCl, 10 mM CaCl2 and 10 mM MgCl2 (pH 7.4) over a minimum period of one week, at 4°C. This solution was selected as being close to our KLH sta…

1990

The determination of average molecular weights and the characterization of molecular weight distributions by the ratio of the weight- to number-average molecular weights Mw/Mn from sedimentation equilibrium in the ultracentrifuge are described. The essential measurement of the density profile of the mixed solvent is conducted according to Munk (Macromolecules15, 500 (1982)). Special evaluation of the polymer band in the equilibrium allowed to deduce from the observed concentration profile Mw and Mn of a series of poly(methyl methacrylate) samples and thus to characterize the molecular weight distribution of the samples.

Characterization of interaction between tricyclic structures containing pharmaceuticals, their models and humic substances.

2011

Their persistence and wide consumption identify pharmaceuticals as “emerging pollutants”. The complexation of pharmaceuticals containing adamantine ring structures and their model substances with humic acids (HA) of different origins was compared using fluorescence spectroscopy as a function of pH, humic acid concentration, ionic strength, and molecular mass of HA. Binding constants between the studied pharmaceuticals and humic acids were calculated. A combination of dynamic and static quenching processes as indicated by nonlinear Stern-Volmer plots and high Kd values were positively correlated with the concentration of carboxyl groups in the studied humic acids. For basic functional group-…

Pharmakologisch-aktive polymere, 21. Orientierende Untersuchungen zur körperverteilung und Ausscheidung von poly[2-(methylsulfinyl)ethylacrylat]en be…

1980

Poly[2-(methylsulfinyl)ethyl acrylate] (1) was synthesized as well as derivatives 14C-labelled in side groups (6) or 14C-labelled in the main chain (11). Polymer 11 with the 14C-labelled main chain was fractionated by precipitation. The η-M-relation determined by measurements of unlabelled polymers in the ultracentrifuge for comparison was used to establish the viscosimetrically determined molecular weights of the labelled fractions. After intravenous application of aqueous solutions of the polymer in rats the excretion rate up to 72 h after treatment was ascertained to ca. 50%; the concentration in the blood serum was found to be strikingly high. A tendency to reinforced storage in organs …

Methods for Separating Native Enzymes

1994

In the course of electrophoresis the stability of an enzyme depends on such conditions as (a) pH-value, (b) ion strength and ion species, (c) effector molecules, (d) temperature and (e) properties of the separation matrix. These parameters were empirically optimized for starch gel electrophoresis [1–3] and cellulose acetate electrophoresis [4, 5] when analyzing predominantly animal and human specimen. A major advantage of these types of separation media is that practically every buffer system can be used to separate enzymes whereas in disc-gel electrophoresis [6–8] the number of applicable buffer systems is limited. When using isoelectric focusing to separate native enzymes no buffer choice…

Determination of molecular weights and Stokes' radii of non-denatured proteins by polyacrylamide gradient gel electrophoresis. 1. An equation relatin…

1982

Untreated and processed gel plates of polyacrylamide (PAA) gradient gels were cut into strips perpendicularly to their length, and the wet and dry matter of the sections was determined. In untreated gels the apparent dry matter, as well as the relative dry matter, are a linear function of the gel length. In processed gels, however, only the apparent gel concentration increases linearly with the gel length, whereas the relative dry matter increases linearly with the square root of the gel length. The %T (content in polyacrylamide) was calculated from the apparent dry matter. The gel gradients used were found to be linear with respect to %T. Six different calibration proteins were run and the…