Experimental Facts Pertaining to the Relationship between Viscosity, Molecular Size, and Molecular Shape.

1942 ◽  
Vol 31 (3) ◽  
pp. 561-586 ◽  
Author(s):  
Max A. Lauffer
Keyword(s):  
Molecular Size ◽  
Molecular Shape ◽  
The Relationship

scholarly journals The oncornavirus glycoprotein gp69/71: a constituent of the surface of normal and malignant thymocytes.

1975 ◽  
Vol 141 (1) ◽  
pp. 172-187 ◽  
Author(s):  
B C Del Vellano ◽  
B Nave ◽  
B P Croker ◽  
R A Lerner ◽  
F J Dixon
Keyword(s):  
Leukemia Virus ◽  
Molecular Size ◽  
Size Class ◽  
Antigenic Determinants ◽  
Lymphoma Cells ◽  
Differentiated Cells ◽  
Interesting Difference ◽  
Associated Proteins ◽  
Related Proteins ◽  
The Relationship

The oncornavirus related proteins associated with the surface of normal and malignant thymocytes were studied. Three virion-associated proteins (gp69/71, p45, p30) were associated with lymphoma cells from about 70% of the tumors studied. Two virion-associated proteins (gp69/71 and p45 were associated with normal thymocytes form some but not all strains of mice. In gp69/71- mice, conversion to the gp69/71+ phenotype accompanied leukemogenesis. An interesting difference in the apparent molecular size of virus related antigens of the 70,000 dalton size class was detected in lymphoma cells present in involved spleens as compared to involved thymuses. Mice infected as neonates with Scripps leukemia virus make antibody to gp69/71 and some make antibodies to molecules associated with the surface of their own tumors. The significance of the restricted presence of antigens coded for by the viral genome to the surface of some differentiated cells is discussed in reference to (a) the relationship between virion, leukemia associated, and differentiation dependent markers, and (b) the possible consequence to the host of having similar antigenic determinants on three independent structures with replicative potential (virus, normal thymocytes, and tumor cells).

Low-Temperature Mobility of Thionine in a Faujasite Cage

1994 ◽  
Vol 366 ◽  
Author(s):  
F. W. Deeg ◽  
M. Ehrl ◽  
C. Bräuchle
Keyword(s):  
Low Temperature ◽  
Pore Structure ◽  
Zeolite Y ◽  
Three Dimensional ◽  
Molecular Size ◽  
Energy Difference ◽  
Temperature Dependent ◽  
Host Interaction ◽  
The Relationship

ABSTRACTWe have used low-temperature optical spectroscopy to characterize the guest/host interaction of thiazine and oxazine dyes encapsulated in the three-dimensional pore structure of faujasite cages. The system thionine in dehydrated zeolite-Y exhibits a thermal and optical equilibrium between two spectroscopically distinguishable species. Temperature-dependent measurements allow the determination of the energy difference and barrier between these two forms as 170 cm−1 and 120 cm−1, respectively. The two forms are associated with two different locations/conformations of the chromophore within the faujasite pore structure. The degree of freedom responsible for the interconversion of the two forms is extremely sensitive to the relationship between molecular size and form of the void.

Studies on the histamine-sensitizing factor of Bordetella pertussis by density gradient centrifugation

1968 ◽  
Vol 14 (5) ◽  
pp. 525-528 ◽  
Author(s):  
B. W. Griffiths ◽  
M. A. Mason
Keyword(s):  
Chemical Composition ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Biological Activities ◽  
Gradient Centrifugation ◽  
Molecular Size ◽  
Protein Profiles ◽  
Foreign Proteins ◽  
Relationship Of ◽  
The Relationship

The density gradient centrifugation of the histamine-sensitizing factor (HSF) of B. pertussis extracts in admixture with purified foreign proteins has revealed a property of the HSF not previously recognized. The HSF sedimentation was markedly accelerated in the presence of human serum macroglobulin and hog thyroglobulin. The absence of gross detectable changes in the protein profiles after the displacement of the HSF by sedimentation suggests the need for studies on the chemical composition of the HSF.The affinity of the HSF towards the foreign proteins, particularly those of large molecular size, has suggested a useful model by which the relationship of the HSF to other biological activities of B. pertussis may be studied.

scholarly journals Enzymatic tracers in the study of vascular permeability.

1979 ◽  
Vol 27 (8) ◽  
pp. 1120-1130 ◽  
Author(s):  
N Simionescu
Keyword(s):  
Vascular Permeability ◽  
Molecular Size ◽  
Molecular Shape ◽  
Enzyme Concentration ◽  
Gel Chromatography ◽  
Microvascular Endothelium ◽  
Tracer Solution ◽  
Molecular Radius

Elucidation of the ultrastructural basis of vascular permeability was aided by the development of cytochemical techniques for visualizing the distribution, within the vessel wall, of intravenously injected peroxidatic enzymes of varying molecular size. Tracer enzymes available range from 10 A (hemeoctapeptide) to 52 A (catalase) effective molecular radius. The use of enzymatic probe molecules assumes a thorough characterization of: (a) the molecular charge (isoelectric point of the native enzyme, and when feasible, its polyanionic and polycationic derivatives; (b) effective molecular radius (ae); (c) peroxidase activity (to detect by spectrophotometry of DAB-oxidizing activity, the optimal pH, temperature, and enzyme concentration to be employed in the cytochemical procedure). Molecular shape and state of dispersion of the enzymatic probes should be determined by gel chromatography and spectrophotometry of both the tracer solution and aliquots of blood plasma collected after i.v. injection of the tracer. Conditions required for the probe administration include: (a) the investigation of potential side effects (tests for toxicity and vascular leakage) and (b) estimation of the tracer volume and concentration which does not affect significantly the blood volume and osmotic pressure. Determination in vitro of the crosslinking of tracer molecules induced by the aldehyde fixative to be employed, also gives an indication on potential diffusion artifacts. Based on the information thus obtained, the design of the cytochemical procedure should also take into account the possible use of methods for enhancing the peroxidatic reaction product: nitrogenous ligands (imidazole, diaminopyrimidine, histidine) or polyphenolic mordants (galloylglucoses). The usefulness of peroxidatic tracers in the investigation of vascular permeability is exemplified by some results obtained on the microvascular endothelium in vivo (trasncytosis, intercellular pathway, etc.), and on endothelial cells isolated from heart microvasculature.

scholarly journals NATIVE AND REGENERATED BOVINE ALBUMIN

1943 ◽  
Vol 26 (6) ◽  
pp. 513-531 ◽  
Author(s):  
Frank W. Putnam ◽  
John O. Erickson ◽  
Elliot Volkin ◽  
Hans Neurath
Keyword(s):  
Guanidine Hydrochloride ◽  
Average Molecular Weight ◽  
Free Fraction ◽  
Molecular Size ◽  
Axial Ratio ◽  
Molecular Shape ◽  
Carbohydrate Content ◽  
Isoelectric Precipitation ◽  
Denatured State ◽  
Bovine Albumin

1. Whole bovine albumin, homogeneous in diffusion and sedimentation, and essentially homogeneous in electrophoresis, has been prepared by a method involving ammonium sulfate precipitation of the globulins in the cold and of the albumin at room temperature, isoelectric precipitation of the euglobulins, and reprecipitation of the albumin. 2. The product has been characterized by chemical analysis and by viscosity, diffusion, sedimentation, and electrophoresis measurements. The carbohydrate content is 0.38 per cent, the nitrogen content, 15.2 per cent. The molecular shape approximates that of a prolate ellipsoid with an axial ratio of 3.1, assuming 33 per cent hydration; the average molecular weight is 65,000. 3. Bovine albumin is readily denatured by concentrated solutions of urea or guanidine hydrochloride, gross changes in molecular shape resulting. 4. Regeneration of bovine albumin denatured in solutions of 8 M urea or guanidine hydrochloride yields a material closely resembling the native in carbohydrate content, in molecular size and shape, and in electrophoretic properties. However, the regenerated protein differs from the native in susceptibility to tryptic digestion, and, in this respect, appears to be in a denatured state. 5. In 8 M solutions of guanidine hydrochloride a limiting yield of regenerated albumin equivalent to 95 per cent of the original protein is approached. 6. Bovine crystalbumin, a crystalline carbohydrate-free fraction of the whole albumin, appears to be more susceptible to denaturation than whole bovine albumin.

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