scholarly journals Some Physicochemical Properties of Erysimum Latent Virus

1982 ◽  
Vol 35 (1) ◽  
pp. 5
Author(s):  
Keith H Gough ◽  
Glenn G Lilley ◽  
Dharma D Shukla ◽  
Frank Woods
Keyword(s):  
Molecular Weight ◽  
Buoyant Density ◽  
Latent Virus ◽  
Sedimentation Equilibrium ◽  
Protein Subunit ◽  
Molecular Weights ◽  
Caesium Chloride ◽  
Rna Content ◽  
Velocity Diffusion ◽  
Phosphorus Determination

Sedimentation velocity, diffusion coefficient and sedimentation equilibrium measurements gave a molecular weight of 5 �90 x 106 for the intact Erysimum latent virus. The molecular weight of the empty shell was estimated to be 3�92 X 106 and the protein subunit to be 21 600. The RNA content calculated from the molecular weights of the full and empty particles is 33 %, in agreement with that estimated from the buoyant density in caesium chloride. However, a direct phosphorus determination gave an RNA content of only 28 %.

scholarly journals The use of equilibrium-density-gradient methods for the preparation and characterization of blood-group-specific glycoproteins

1970 ◽  
Vol 117 (5) ◽  
pp. 879-891 ◽  
Author(s):  
J. M. Creeth ◽  
M. A. Denborough
Keyword(s):  
Molecular Weight ◽  
Density Gradient ◽  
Blood Group ◽  
Buoyant Density ◽  
Gradient Methods ◽  
Apparent Molecular Weight ◽  
Sedimentation Equilibrium ◽  
Equilibrium Density ◽  
Caesium Chloride ◽  
Selective Solvation

1. The method of sedimentation equilibrium in a gradient of caesium chloride has been applied to the preparation of blood-group-specific glycoproteins from human ovarian-cyst fluids: it is shown that virtually complete separation from contaminating protein is easily accomplished in a single step. 2. The glycoproteins isolated in this way have been characterized by analytical density-gradient experiments in both caesium chloride and caesium sulphate and values of the buoyant density, selective solvation and apparent molecular weight have been obtained. 3. In some cases, materials prepared from the same cysts by solvent extraction methods have also been characterized in these terms. 4. The selective solvation values are about 0.1 and 0.5g of water/g of glycoprotein in caesium chloride and caesium sulphate respectively. 5. The apparent molecular-weight values are much lower than the weight-average molecular weights, and it is shown that the origin of the discrepancy is heterogeneity in density of the glycoproteins. 6. Some sources of error in the interpretation of density-gradient schlieren patterns are examined.

scholarly journals The proteins of Xenopus ovary ribosomes

1971 ◽  
Vol 125 (4) ◽  
pp. 1091-1107 ◽  
Author(s):  
P J Ford
Keyword(s):  
Potassium Chloride ◽  
Ribosomal Proteins ◽  
Large Subunit ◽  
Buoyant Density ◽  
Small Subunit ◽  
Chemical Methods ◽  
Ribosomal Subunits ◽  
Molecular Weights ◽  
Caesium Chloride ◽  
Chloride Treatment

1. The preparation of ribosomes and ribosomal subunits from Xenopus ovary is described. 2. The yield of once-washed ribosomes (buoyant density in caesium chloride 1.601g·cm-3; 44% RNA, 56% protein by chemical methods) was 10.1mg/g wet wt. of tissue. 3. Buoyant density in caesium chloride and RNA/protein ratios by chemical methods have been determined for ribosome subunits produced by 1.0mm-EDTA or 0.5m-potassium chloride treatment and also for EDTA subunits extracted with 0.5m-, 1.0m- or 1.5m-potassium chloride, 4. Analysis of ribosomal protein on acrylamide gels at pH4.5 in 6m-urea reveals 24 and 26 bands from small and large EDTA subunits respectively. The actual numbers of proteins are greater than this, as many bands are obviously doublets. 5. Analysis of the proteins in the potassium chloride extract and particle fractions showed that some bands are completely and some partially extracted. Taking partial extraction as an indication of possible doublet bands it was found that there were 12 and 20 such bands in the small and large subunits respectively, making totals of 36 and 46 proteins. 6. From the measured protein contents and assuming weight-average molecular weights for the proteins of large and small subunits close to those observed for eukaryote ribosomal proteins it is possible to compute the total numbers of protein molecules per particle. It appears that too few protein bands have been identified on acrylamide gels to account for all the protein in the large subunit, but probably enough for the small subunit.

scholarly journals Sedimentation-equilibrium studies on the heterogeneity of two β-lactamases

1970 ◽  
Vol 118 (3) ◽  
pp. 467-474 ◽  
Author(s):  
P. H. Lloyd ◽  
A. R. Peacocke
Keyword(s):  
Molecular Weight ◽  
Diffusion Coefficients ◽  
Minor Component ◽  
Theoretical Solution ◽  
Sedimentation Equilibrium ◽  
Equilibrium Studies ◽  
Molecular Weights ◽  
A Minor

Solutions of crystalline β-lactamase I and β-lactamase II, prepared by Kuwabara (1970), were examined in the ultracentrifuge and their sedimentation coefficients, diffusion coefficients, molecular weights and heterogeneity determined. Each sample was shown to consist of a major component comprising at least 97% of the material and a minor component of much higher molecular weight. The molecular weights of the major components were 27800 for β-lactamase I and 35600 for β-lactamase II. Emphasis is placed on a straightforward practical way of analysing the sedimentation-equilibrium results on mixtures of two macromolecular components rather than on a strict theoretical solution. Appendices describe the theory of systems at both chemical and sedimentation equilibrium and the procedure for calculating the combined distribution of two components.

Behavior of Rubber Hydrocarbon in a Molecular Still

1939 ◽  
Vol 12 (4) ◽  
pp. 789-793 ◽  
Author(s):  
W. Harold Smith ◽  
Henry J. Wing
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
High Molecular Weight ◽  
Molecular Species ◽  
Decomposition Temperature ◽  
Sedimentation Equilibrium ◽  
Chain Molecules ◽  
Molecular Weights ◽  
Average Value ◽  
Long Chain

Abstract Some investigators believe that rubber consists of associated molecules, and others accept Staudinger's view that long-chain molecules are formed by polymerization. Pummerer, Andriessen and Gündel have obtained a molecular weight as low as 600. Meyer and Mark believe that it is approximately 5,000, although they calculated on the basis of osmotic pressures values as high as 350,000. They, as well as Pummerer, consider that rubber is an associated colloid and that high molecular weights are caused by aggregates, sometimes called micelles. Staudinger, however, considers that the long-chain rubber molecule itself has a molecular weight of 200,000 or even 350,000, and that products with lower values, which may be formed in rubber, result from degradation. if the molecules are small it might be possible to distil them if their vapor pressure could be sufficiently increased, but none would distil without decomposition if the molecules are very large. Because the vapor pressure of rubber below its decomposition temperature is low, it appeared of interest to attempt to distil the material in a molecular still. Paraffin wax and sugar, both substances of relatively high molecular weight, have been successfully distilled in this type of apparatus. Subsequent to the work described in this paper, the molecular weight of sol rubber prepared at this Bureau was determined by Kraemer and Lansing of E. I. du Pont de Nemours & Co., Inc. They used the Svedberg method of sedimentation equilibrium in an ultracentrifuge with ethereal solutions of sol rubber. The temperature of the solutions during determinations was approximately 10° C, and an average value of 460,000 was obtained. There was evidenced of a mixture of molecular species.

scholarly journals Particle weights and protein composition of the ribosomal subunits of the extremely thermoacidophilic archaebacterium Caldariella acidophila

1983 ◽  
Vol 209 (2) ◽  
pp. 461-470 ◽  
Author(s):  
P Londei ◽  
A Teichner ◽  
P Cammarano ◽  
M De Rosa ◽  
A Gambacorta
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Buoyant Density ◽  
Protein Composition ◽  
Equilibrium Density ◽  
Number Average Molecular Weight ◽  
Ribosomal Subunits ◽  
Molecular Weights ◽  
Protein Components ◽  
Protein Number

1. The ribosomal subunits of one thermoacidophilic archaebacterium (Caldariella acidophila) and of two reference eubacterial species (Bacillus acidocaldarius, Escherichia coli) were compared with respect to ribosome mass and protein composition by (i) equilibrium-density sedimentation of the particles in CsCl and (ii) gel-electrophoretic estimations of the molecular weights of the protein and the rRNA. 2. By either procedure, it is estimated that synthetically active archaebacterial 30S subunits (52% protein by wt.) are appreciably richer in protein than the corresponding eubacterial particles (31% protein by wt.) 3. The greater protein content of the archaebacterial 30S subunits is accounted for by both a larger number and a greater average molecular weight of the subunit proteins; specifically, C. acidophila 30S subunits yield 28 proteins whose combined mass is 0.6×10(6) Da, compared with 20 proteins totalling 0.35×10(6) Da mass for eubacterial 30S subunits. 4. No differences in protein number are detected among the large subunits, but C. acidophila 50S subunits exhibit a greater number-average molecular weight of their protein components than do eubacterial 50S particles. 5. Particle weights estimated by either buoyant-density data, or molecular weights of rRNA plus protein, agree to within less than 2%. By either procedure C. acidophila 30S subunits 1.15×10(6) Da mass) are estimated to be about 300 000 Da heavier than their eubacterial counterparts (0.87×10(6) Da mass); a smaller difference. 0.15×10(6) Da, exists between the archaebacterial and the eubacterial 50S subunits (respectively 1.8×10(6) and 1.65×10(6) Da). It is concluded that the heavier-than-eubacterial mass of the C. acidophila ribosomes resides principally in their smaller subunits.

scholarly journals Molecular Weight of Two Oncornavirus Genomes: Derivation from Particle Molecular Weights and RNA Content

1974 ◽  
Vol 14 (6) ◽  
pp. 1388-1393 ◽  
Author(s):  
A. R. Bellamy ◽  
S. C. Gillies ◽  
J. D. Harvey
Keyword(s):  
Molecular Weight ◽  
Molecular Weights ◽  
Rna Content

scholarly journals Kinetic complexity of chloroplastal deoxyribonucleic acid and mitochondrial deoxyribonucleic acid from higher plants

1969 ◽  
Vol 112 (5) ◽  
pp. 777-786 ◽  
Author(s):  
Richard Wells ◽  
Max Birnstiel
Keyword(s):  
Molecular Weight ◽  
Mitochondrial Dna ◽  
Gaussian Distribution ◽  
Deoxyribonucleic Acid ◽  
Nuclear Dna ◽  
Higher Plants ◽  
Buoyant Density ◽  
Cell Fractionation ◽  
Caesium Chloride ◽  
Cellular Dna

1. Chloroplasts and mitochondria were isolated by aqueous and non-aqueous cell-fractionation techniques. In a variety of higher plants the mitochondrial DNA bands in a caesium chloride gradient at 1·706g.cm.−3, whereas chloroplastal DNA has a buoyant density of 1·697g.cm.−3. 2. In total cellular DNA of moderate molecular weight, the chloroplastal DNA is found within the Gaussian distribution of the nuclear DNA and is not resolved as a satellite. 3. Both chloroplastal DNA and mitochondrial DNA from lettuce renature rapidly. 4. The kinetic complexity of mitochondrial DNA is > 108 daltons. 5. Chloroplastal DNA is made up from fast and slow renaturing sequences with kinetic complexities of 3×106 and 1·2×108 daltons respectively. 6. From the discrepancy between analytical and kinetic complexity it is concluded that chloroplastal DNA is extensively reiterated.

scholarly journals Molecular weights of the Thy-1 glycoproteins from rat thymus and brain in the presence and absence of deoxycholate

1978 ◽  
Vol 169 (2) ◽  
pp. 411-417 ◽  
Author(s):  
P W Kuchel ◽  
D G Campbell ◽  
A N Barclay ◽  
A F Williams
Keyword(s):  
Molecular Weight ◽  
Equilibrium Dialysis ◽  
Sedimentation Coefficient ◽  
Sedimentation Equilibrium ◽  
Membrane Glycoproteins ◽  
Guanidinium Chloride ◽  
Molecular Weights ◽  
Methionine Residue ◽  
Disulphide Bonds ◽  
Binding Data

1. The Thy-1 membrane glycoproteins from rat thymus and brain bound deoxycholate to 24% of their own weight as measured by equilibrium dialysis. The binding occurred co-operatively at the critical micelle concentration of deoxycholate, suggesting that the glycoproteins bind to a micelle, and not to the detergent monomer. 2. From sedimentation-equilibrium and deoxycholate-binding data the molecular weights of the glycoprotein monomers were calculated to be 18700 and 17500 for thymus and brain Thy-1 glycoprotein monomers were calculated to be 18700 and 17500 for thymus and brain Thy-1 glycoproteins respectively. The molecular weight of the polypeptide part of the glycoprotein is thus 12500. 3. In the absence of deoxycholate, brain or thymus Thy-1 glycoprotein formed large homogeneous complexes of mol. wt. 270000 or 300000 respectively. The sedimentation coefficient of these was 12.8 S. The complex was only partially dissociated by 4M-guanidinium chloride. 4. After cleavage of brain or thymus Thy-1 glycoprotein with CNBr, two peptides were clearly identified. They were linked by disulphide bonds and both contained carbohydrate. This cleavage suggests there is only one methionine residue per molecule, which is consistent with the above molecular weights and the known amino acid composition.

scholarly journals Molecular Weight Distribution Studies on Heparin

1977 ◽  
Author(s):  
Grant H. Barlow
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Gel Filtration ◽  
Equilibrium Analysis ◽  
Resolving Power ◽  
Sedimentation Equilibrium ◽  
Distribution Data ◽  
Molecular Weights ◽  
Distribution Studies

The determination of molecular weight distribution using the sedimentation equilibrium analysis developed for polymers by T. Scholte (J. Polymer Sei, 6, 111, 1968) has been adapted for heparin analysis. Pork mucosal heparin separated into molecular weight subfractions by gel filtration on Ultrogel AcA44 (L.K.B.) was used to test the validity and resolving power of the method. Results indicate that the method is able to differentiate molecular weight distribution satisfactorily. Comparisons have been made of molecular weight distribution of samples from different species, organs and manufacturers. Average molecular weights for most samples center around 15,000 Dal tons, but samples show considerable variation in their distribution data. Results suggest that variations between manufacturers is more pronounced than the specie and organ difference indicating the importance of the purification procedure.

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