Search results for "Ultracentrifuge"

Distribution of chlorpromazine in a simplified blood influenced by various drugs

1973

The binding of chlorpromazine to erythrocytes and to albumin as influenced by other drugs was studied in a simplified blood (31.5±0.3% bovine erythrocytes, 4 g-% bovine serum albumin in 0.02 M phosphate buffer solution containing 0.15 M NaCl). the total concentration of chlorpromazine in the simplified blood was 10−4 M, the concentration of the displacing drugs was 10−3 M. After an incubation period of 3 h at 22° C the chlorpromazine concentration was determined in the albumin solution after centrifugation of the blood at 3000×g and in the aqueous phase after ultracentrifugation at 150000×g. Under control conditions 68.1±0.9% of chlorpromazine was bound to the erythrocytes, 28.5±0.9% was bo…

Physicochemical characterization of the fifth (C5), sixth (C6), seventh (C7), eighth (C8) and ninth (C9) component of guinea pig complement.

1971

A physicochemical characterization of the purified guinea pig complement components C5 to C9 is given. For this purpose the sedimentation rate, the diffusion coefficient, the molecular weight and the isoelectric point were determined and compared with the values already known for the guinea pig and human complement system. For the determination of the physicochemical parameters gel filtration on Sephadex G-200, ultracentrifugation applying a sucrose density gradient and thin-layer isoelectric focusing were used. By comparing the values of the human and guinea pig complement a remarkable similarity is shown.

ATR-FTIR spectroscopy for the routine quality control of exosome isolations

2021

Abstract Exosomes are nanosized vesicles containing specific cargos of DNA, RNA, proteins, metabolites, and intracellular and membrane lipids. Exosome isolation needs to be optimized carefully depending on the type of biofluid and tissue and the retrieved exosomes need to be characterized. The main objective of this study was to determine the feasibility of a multimodal analysis of Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and UPLC–QqTOF-MSMS for the development of a routine quality control tool of isolated exosomes and the rapid characterization of their lipid profiles and total protein content. Using human milk as model example, exosomes were isolat…

Gastric histamine methyltransferase: Different methylation rates for enantiomers of side-chain methylated histamine analogues using a highly purified…

1984

The inhibitor/activator and substrate properties of enantiomers of two methylated histamines (MH) were investigated using a histamine methyltransferase preparation which was purified 1207-fold from pig fundic mucosa by ultracentrifugation, ion-exchange chromatography on DEAE-cellulose and preparative electrofocusing. In 1-100 microM concentrations, S-alpha-MH and R-alpha-MH were acceptor substrates as good as histamine itself. When substrate concentrations were increased to 1 mM these substances were methylated to an even greater extent than histamine, since they did not exert substrate inhibition on HMT. Introduction of a further methyl-group into the N alpha-position reduced acceptor subs…

Isolation and purification of plasmids from Bacteroides fragilis using rubidium trichloroacetate density gradient centrifugation.

1983

A rapid and easy final purification method is described for the isolation of plasmids from B. fragilis. Using RbTCA density gradient centrifugation in an airfuge ultracentrifuge ccc plasmid DNA can be separated from RNA, residual chromosomal DNA, linear and oc plasmid DNA. Pure ccc plasmid DNA is obtained from cultures of between 1 ml and 2 l in less than one day.

The molecular heterogeneity of hemocyanin: Structural and functional properties of the 4×6-meric protein of Upogebia pusilla (Crustacea)

2006

The structural properties of the hemocyanin isolated from the Mediterranean mud shrimp, Upogebia pusilla (Decapoda: Thalassinidea), were investigated. Our intent was to make use of the U. pusilla case to perform a structural comparison between crustacean and chelicerate 4×6-meric hemocyanins. The thalassinidean hemocyanin appears similar in size but different in structural organization compared to the chelicerate 4×6-mer. Ultracentrifuge analyses on the purified protein revealed a sedimentation coefficient of 39S, typical of 4×6 hemocyanins. Electron micrographs are in agreement with a model in which four 2×6-meric building blocks are arranged in a tetrahedron-like quaternary structure and …

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.

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 …

Separation of chitosomal chitin synthetase from cell-free extracts ofNeurospora crassa “Slime” variant agglutinated with concanavalin A

1989

Cell-free extracts of the wall-less slime variant ofNeurospora crassa were treated with concanavalin A (Con A); this treatment caused a massive agglutination of the particulate structures in the cell-free homogenate, although most (73%) of the chitin synthetase initially present in the cell-free extract remained in the supernatant obtained after sedimentation of the lectin-flocculated material. This chitin synthetase showed the sedimentation properties of chitosomes (unique microvesicular structures) and failed to bind [3H]Con A. A significant percentage (42%) of the chitin synthetase activity associated with the Con A-flocculated material probably corresponds to mechanically trapped chitos…

Native and subunit molecular mass and quarternary structure of the hemoglobin from the primitive branchiopod crustacean Triops cancriformis

2006

Many branchiopod crustaceans are endowed with extracellular, high-molecular-weight hemoglobins whose exact structural characteristics have remained a matter of conjecture. By using a broad spectrum of techniques, we provide precise and coherent information on the hemoglobin of one of the phylogenetically ‘oldest’ extant branchiopods, the tadpole shrimp Triops cancriformis. The hemoglobin dissociated under reducing conditions into two subunits, designated TcHbA and TcHbB, with masses of 35 775 ± 4 and 36 055 ± 4 Da, respectively, determined by ESI-MS. Nonreducing conditions showed only two disulfide-bridged dimers, a homodimer of TcHbA, designated D1 (71 548 ± 5 Da), and the heterodimer D2 (…