scholarly journals The dipolar origin of protein relaxation

1968 ◽  
Vol 110 (3) ◽  
pp. 419-424 ◽  
Author(s):  
H. Hendrickx ◽  
R. Verbruggen ◽  
M. Y. Rosseneu-Motreff ◽  
V. Blaton ◽  
H. Peeters

1. A set of parameters is proposed to check the interpretation of the dielectric behaviour of protein solutions as a rigid-dipole relaxation of prolate ellipsoids of revolution in the frequency range between 20 kHz and 10 MHz. Besides the δb-function of Scheraga, another analogous function (δa) is presented to establish size and shape of globular proteins. A study of the influence of solvent viscosity on the dielectric dispersion also gives strong evidence in favour of rigid-dipole relaxation. 2. Measurements of the dielectric dispersion of monomer solutions of bovine serum albumin and transferrin are reported. Monomers of bovine serum albumin were obtained by fractionation on Sephadex G-150. Low-conductivity solutions of both proteins are obtained by passage through an ion-exchange resin. 3. Computer analysis of the experimental dispersion curves by use of a two-term Debye dispersion gives valuable information about transferrin and leads to an axial ratio 4·5 for a prolate ellipsoid of revolution. The dielectric increment of bovine serum albumin is very low and no conclusive results have yet been obtained.

1977 ◽  
Vol 22 (6) ◽  
pp. 1160-1167 ◽  
Author(s):  
C G Essex ◽  
M S Symonds ◽  
R J Sheppard ◽  
E H Grant ◽  
R Lamote ◽  
...  

1955 ◽  
Vol 33 (6) ◽  
pp. 1043-1054 ◽  
Author(s):  
P. A. Charlwood

Sedimentation and viscosity measurements were made on bovine serum albumin during denaturation at pH 9.9 in 8.0 M urea in the presence of sodium-p-chloromercuribenzoate. The results suggested that the urea caused a rapid initial increase in the axial ratio and equivalent volume of the protein molecule. A subsequent slower increase in asymmetry was attributed to the effect of the mercury compound.


Author(s):  
G. D. Gagne ◽  
M. F. Miller

We recently described an artificial substrate system which could be used to optimize labeling parameters in EM immunocytochemistry (ICC). The system utilizes blocks of glutaraldehyde polymerized bovine serum albumin (BSA) into which an antigen is incorporated by a soaking procedure. The resulting antigen impregnated blocks can then be fixed and embedded as if they are pieces of tissue and the effects of fixation, embedding and other parameters on the ability of incorporated antigen to be immunocyto-chemically labeled can then be assessed. In developing this system further, we discovered that the BSA substrate can also be dried and then sectioned for immunolabeling with or without prior chemical fixation and without exposing the antigen to embedding reagents. The effects of fixation and embedding protocols can thus be evaluated separately.


1981 ◽  
Vol 46 (03) ◽  
pp. 645-647 ◽  
Author(s):  
M A Orchard ◽  
C Robinson

SummaryThe biological half-life of prostacyclin in Krebs solution, human cell-free plasma or whole blood was measured by bracket assay on ADP-induced platelet aggregation. At 37°C, pH 7.4, plasma and blood reduced the rate of loss of antiaggregatory activity compared with Krebs solution. The protective effect of plasma was greater than that of whole blood. This effect could be partially mimicked by the addition of human or bovine serum albumin to the Krebs solution. The stabilisation afforded by human serum albumin was dependent on the fatty acid content of the albumin, although this was less important for bovine serum albumin.


1974 ◽  
Vol 75 (1) ◽  
pp. 133-140 ◽  
Author(s):  
B. E. Senior

ABSTRACT A radioimmunoassay was developed to measure the levels of oestrone and oestradiol in 0.5–1.0 ml of domestic fowl peripheral plasma. The oestrogens were extracted with diethyl ether, chromatographed on columns of Sephadex LH-20 and assayed with an antiserum prepared against oestradiol-17β-succinyl-bovine serum albumin using a 17 h incubation at 4°C. The specificity, sensitivity, precision and accuracy of the assays were satisfactory. Oestrogen concentrations were determined in the plasma of birds in various reproductive states. In laying hens the ranges of oestrone and oestradiol were 12–190 pg/ml and 29–327 pg/ml respectively. Levels in immature birds, in adult cockerels and in an ovariectomized hen were barely detectable. The mean concentrations of oestrone and oestradiol in the plasma of four non-laying hens (55 pg/ml and 72 pg/ml respectively) and one partially ovariectomized hen (71 pg/ml and 134 pg/ml respectively) were well within the range for laying hens. It is evident that the large, yolk-filled follicles are not the only source of oestrogens in the chicken ovary.


2013 ◽  
Vol 30 (2) ◽  
pp. 232
Author(s):  
Fan LIU ◽  
Yuanqin ZHANG ◽  
Zhijin ZHANG

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