scholarly journals THE EFFECTS OF CATHODE RAYS ON THE PROTEINS OF SERUM

1929 ◽  
Vol 50 (4) ◽  
pp. 439-444
Author(s):  
Lillian E. Baker ◽  
Robert B. Corey
Keyword(s):  
Beneficial Effect ◽  
Isoelectric Point ◽  
Protein Molecule ◽  
Hydrolytic Cleavage ◽  
Trichloracetic Acid ◽  
Characteristic Appearance ◽  
Sh Groups ◽  
Denatured Protein ◽  
Retarding Effect

The effects of cathode rays on the proteins of serum appear to be (1) denaturation of a large proportion of the albumin and globulin with the formation of products that are soluble at the pH of the serum; (2) the production of a tough and exceedingly insoluble substance on the window of the cell where most of the absorption of electrons occurs; (3) a slight hydrolytic cleavage of the protein molecule producing a small quantity of products having properties so near to those of the protein that they are precipitated by trichloracetic acid but are not removed by coagulation at the isoelectric point; (4) the production of a small amount of hydrolytic products not precipitated by trichloracetic acid; and (5) the formation of a small amount of ammonia, part of which at least is derived from the urea in the serum. It is interesting to note that these changes are such as would bring about exactly those effects on fibroblasts which were observed when cultures were grown in serum which had been subjected to cathode ray irradiation. The proteins of serum have a retarding effect on the growth of fibroblasts. We might, therefore, expect their removal by denaturation and coagulation to result in the slightly larger growth which was observed. The production of SH groups in the denatured protein molecule would also tend to have a beneficial effect, as has been observed in experiments with denatured albumin. A concentration of protein split products equal to that in the irradiated sera has been observed to produce cells of characteristic appearance, full of cytoplasmic granulations and possessing long, active pseudopods, such as those noted in colonies cultivated in serum which had been subjected to cathode rays.

scholarly journals SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS

1936 ◽  
Vol 19 (3) ◽  
pp. 427-438 ◽  
Author(s):  
A. E. Mirsky ◽  
M. L. Anson
Keyword(s):  
Serum Albumin ◽  
Quantitative Methods ◽  
Protein Denaturation ◽  
Protein Molecule ◽  
Insoluble Fraction ◽  
Egg Albumin ◽  
Sh Groups ◽  
Denatured Protein ◽  
Hydrolyzed Protein ◽  
Air Water Interface

1. In native egg albumin no SH groups are detectable, whereas in completely coagulated albumin as many groups are detectable as are found in the hydrolyzed protein. In egg albumin partially coagulated by heat the soluble fraction contains no detectable groups, and the insoluble fraction contains the number found after hydrolysis. 2. In the reversal of denaturation of serum albumin, when insoluble protein regains its solubility, S-S groups which have been detectable in the denatured protein, disappear. 3. When egg albumin coagulates at an air-water interface, all the SH groups in the molecule become detectable. 4. In egg albumin coagulated by irradiation with ultraviolet light, the same number of SH groups are detectable as in albumin coagulated by a typical denaturing agent. 5. When serum albumin is denatured by urea, there is no evidence that S-S groups appear before the protein loses its solubility. 6. Protein denaturation is a definite chemical reaction: different quantitative methods agree in estimates of the extent of denaturation, and the same changes are observed in the protein when it is denatured by different agents. A protein molecule is either native or denatured. The denaturation of some proteins can be reversed.

The Relationship of Properties of Synthetic Poly(Isoprene) and Natural Rubber in The Factory. The Effect of Non-Rubber Constituents of Natural Rubber

1973 ◽  
Vol 46 (1) ◽  
pp. 47-66 ◽  
Author(s):  
E. C. Gregg ◽  
J. H. Macey
Keyword(s):  
Natural Rubber ◽  
Protein Molecule ◽  
Insoluble Fraction ◽  
Prosthetic Group ◽  
Rubber Material ◽  
Green Strength ◽  
Denatured Protein ◽  
Low Concentrations ◽  
Relationship Of ◽  
The Relationship

Abstract The causes of some of the differences in properties between compounded natural rubber and compounded synthetic poly (isoprene) have been traced to the insoluble non-rubber material in natural rubber. This material is mostly denatured proteins and is responsible for the higher modulus, faster scorch time, higher heat buildup, and higher hot tear strength of natural rubber. These properties may be related to the pigment effect of the denatured protein to act as a reinforcing filler at low concentrations (3–4 per cent by wt) as well as a curing activator. The greater green strength of compounded natural rubber has been related to its more perfect configurational regularity which contributes to faster crystallization. The crystallite concentration increases with increasing stress and the crystallites act like a reversible reinforcing pigment which disappears when the stress is released. The faster plastication rate has been related to the synthetic stabilizers used. Natural rubber hydrocarbon has been shown to be a high molecular lactone arranged in a six membered ring. We speculate natural rubber forms as a prosthetic group connected through a lactone linkage (or the δ-hydroxy acid precursor to the lactone) to a protein molecule in the cell of hevea brasiliensis. It is this structure of a high molecular weight hydrocarbon (natural rubber) attached to a (denatured) protein molecule that accounts for the remarkable dispersability of the insoluble fraction of natural rubber in rubber solvents : the rubber end of the structure tends to dissolve in the rubber solvent while the highly polar, insoluble protein end prevents solution. This structure is the reverse of a micelle in water in principle.

scholarly journals Investigating the Conformation of S100β Protein Under Physiological Parameters Using Computational Modeling: A Clue for Rational Drug Design

2018 ◽  
Vol 12 (1) ◽  
pp. 36-50 ◽  
Author(s):  
Elvis K. Tiburu ◽  
Ibrahim Issah ◽  
Mabel Darko ◽  
Robert E. Armah-Sekum ◽  
Stephen O. A. Gyampo ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Conformational Changes ◽  
Metal Binding ◽  
Binding Sites ◽  
Conformational Dynamics ◽  
Protein Molecule ◽  
Rational Drug Design ◽  
Characteristic Appearance ◽  
Secondary Structure Analysis ◽  
S100β Protein

Background: Physiochemical factors such as temperature, pH and cofactors are well known parameters that confer conformational changes in a protein structure. With S100β protein being a metal binding brain-specific receptor for both extracellular and intracellular functions, a change in conformation due to the above-mentioned factors, can compromise their cellular functions and therefore result in several pathological conditions such as Alzheimer’s disease, Ischemic stroke, as well as Myocardial Infarction. Objective: The studies conducted sought to elucidate the effect of these physiological factors on the conformational dynamics of S100β protein using computational modeling approaches. Method: Temperature-dependent and protein-cofactor complexes molecular dynamics simulations were conducted by varying the temperature from 100 to 400K using GROMACS 5.0.3. Additionally, the conformational dynamics of the protein was studied by varying the pH at 5.0, 7.4 and 9.0 using Ambertools17. This was done by preparing the protein molecule, solvating and minimizing its energy level as well as heating it to the required temperature, equilibrating and simulating under desired conditions (NVT and NPT ensembles). Results: The results show that the protein misfolds as a function of increasing temperature with alpha helical content at 100K and 400K being 57.8% and 43.3%, respectively. However, the binding sites of the protein was not appreciably affected by temperature variations. The protein displayed high conformational instability in acidic medium (pH ~5.0). The binding sites of Ca2+, Mg2+ and Zn2+ were identified and each exhibited different groupings of the secondary structural elements (binding motifs). The secondary structure analysis revealed different conformational changes with the characteristic appearance of two beta hairpins in the presence of Zn2+and Mg2+. Conclusion: High temperatures, different cofactors and acidic pH confer conformational changes to the S100β structure and these results may inform the design of novel drugs against the protein.

Inhibition of Ribonuclease Activity by Bentonite

1973 ◽  
Vol 51 (11) ◽  
pp. 1558-1565 ◽  
Author(s):  
G. G. Jacoli ◽  
W. P. Ronald ◽  
L. Lavkulich
Keyword(s):  
Cation Exchange Capacity ◽  
Protein Molecule ◽  
Exchange Capacity ◽  
Ribonuclease Activity ◽  
X Ray Diffraction ◽  
Tertiary Structures ◽  
Similar Treatment ◽  
X Ray ◽  
Denatured Protein ◽  
Clay Matrix

The inhibition of ribonuclease activity by bentonite and the adsorption of the protein molecule within the clay matrix were assessed by enzyme and X-ray diffraction analysis, respectively.Pretreatment of bentonite with EDTA, potassium, barium, and barium–EDTA caused varying expansion of the d(001) spacing of the clay. The d(001) variation was sensitive to pH.Inhibition of the enzyme activity generally followed the pattern of expansion of the d(001) spacing of the clay, but failed when the interlayers of bentonite expanded beyond their maximum capability.Vermiculite, which is a clay having a higher cation exchange capacity than bentonite, did not expand from the normal state after similar treatment nor did it inhibit ribonuclease activity.When the secondary and tertiary structures of the protein molecule were disrupted, the denatured protein still entered the interlayers of bentonite, but caused a greater expansion of the d(001) spacing than the native ribonuclease.

scholarly journals SULFHYDRYL GROUPS OF EGG ALBUMIN IN DIFFERENT DENATURING AGENTS

1941 ◽  
Vol 24 (6) ◽  
pp. 709-723 ◽  
Author(s):  
A. E. Mirsky
Keyword(s):  
Isoelectric Point ◽  
Guanidine Hydrochloride ◽  
Sulfhydryl Groups ◽  
Color Reaction ◽  
Neutral Medium ◽  
Egg Albumin ◽  
Sh Groups ◽  
Cysteine Content

1. The reaction between ferricyanide and egg albumin in solutions of urea, guanidine hydrochloride, and Duponol has been investigated. 2. In neutral medium ferricyanide oxidizes all the SH groups of egg albumin that give a color reaction with nitroprusside. In neutral medium ferricyanide appears to react only with the SH groups of egg albumin. The quantity of ferrocyanide formed can accordingly be considered the equivalent of the number of SH groups in egg albumin detectable with nitroprusside. 3. In solutions of urea, guanidine hydrochloride, and Duponol sufficiently concentrated so that all the egg albumin present is denatured, the same number of SH groups are found—equivalent to a cysteine content of 0.96 per cent. 4. In denaturation of egg albumin loss of solubility (solubility not in presence of the denaturing agent, but solubility examined in water at the isoelectric point) and appearance of reactive SH groups are integral parts of the same process. As denaturation proceeds in urea, SH groups are liberated only in the egg albumin with altered solubility and in this albumin the maximum number of SH groups is liberated. In a molecule of egg albumin either all of its SH groups that give a test with nitroprusside are liberated or none of them are.

PHYSICAL AND CHEMICAL PROPERTIES OF GLUTEN I. ESTIMATION OF MOLECULAR PROPERTIES USING ELECTROPHORETIC AND DIFFUSION DATA

1949 ◽  
Vol 27c (3) ◽  
pp. 103-124 ◽  
Author(s):  
J. R. Colvin ◽  
A. G. McCalla
Keyword(s):  
Isoelectric Point ◽  
Sodium Salicylate ◽  
Selective Adsorption ◽  
High Surface ◽  
Chemical Properties ◽  
Protein Molecule ◽  
Molecular Characteristics ◽  
Mean Values ◽  
Degree Of Hydration ◽  
Dispersing Agent

The molecular characteristics of gluten in sodium salicylate solutions have been studied by means of diffusion and electrophoretic techniques. The results of the observations indicate that gluten in sodium salicylate is electrostatically homogeneous with a high mean negative valence of 34 and therefore a high surface charge density. The isoelectric point of gluten in this dispersing agent is below pH 4.0. This low value of the isoelectric point and the high valence of the protein molecule is probably due to selective adsorption of salicylate ions on gluten. The particles in the fraction of gluten molecularly dispersed in 0 5 μ sodium salicylate are prolate ellipsoids of revolution of the order of 25 Å in diameter and 400 to 450 Å long. These are mean values as the molecularly dispersed particles are not uniform in mass. When they are aggregated it is side by side association rather than end to end. The density of dehydrated gluten is 1.291 gm. per cc. Qualitative evidence is given for the view that the degree of hydration of gluten particles is probably not great.

scholarly journals Studies on Ovalbumin I. Denaturation By Heat, and the Heterogeneity of Ovalbumin

1964 ◽  
Vol 17 (1) ◽  
pp. 261 ◽  
Author(s):  
MB Smith
Keyword(s):  
Ionic Strength ◽  
Isoelectric Point ◽  
Protein Concentration ◽  
Optical Rotation ◽  
The State ◽  
Denatured Protein ◽  
Reduced Viscosity

The denaturation of ovalbumin by heat at pH 2-3 hus been studied by following the changes in optical rotation, viscosity, solubility at the isoelectric point, and amount of aggregated protein observed in the ultracentrifuge. The laevorotation and reduced viscosity of heated solutions of ovalbumin increa�se with ionic strength and protein concentration. This effect is related to the state of aggregation of the denatured protein and not to the extent of denaturation as measured by changes in solubility. The initial denaturation step is irreversible but does not involve the extensive unfolding observed in urea solutions.

scholarly journals The effect of prednisolone on the course of myocardial infarction

1981 ◽  
Vol 62 (5) ◽  
pp. 14-18
Author(s):  
Z. S. Khasanov
Keyword(s):  
Myocardial Infarction ◽  
Beneficial Effect ◽  
Serum Enzymes ◽  
Protein Fractions ◽  
Complex Treatment ◽  
Sh Groups ◽  
Daily Urine ◽  
Natriuretic Effect

85 patients with large-focal myocardial infarction aged from 38 to 72 years were examined. All patients received complex treatment, and 42 of them received additional prednisolone at a dose of 20-25 mg per day by mouth in the first 6-8 days from the onset of the disease. Studies have shown that the inclusion of prednisolone in the treatment complex has a beneficial effect on the course of myocardial infarction: it accelerates the normalization of protein SH-groups, protein fractions, serum enzymes, electrolytes in the blood and catecholamines in daily urine, gives a diuretic and natriuretic effect without causing an increase in caliuresis.

scholarly journals SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS

1936 ◽  
Vol 19 (4) ◽  
pp. 559-570 ◽  
Author(s):  
A. E. Mirsky
Keyword(s):  
Skeletal Muscle ◽  
Crystalline Lens ◽  
Protein Fractions ◽  
Sh Groups ◽  
Denatured Protein ◽  
Native Proteins ◽  
Denatured Proteins ◽  
Single Exception ◽  
Minced Muscle

1. In the denatured proteins of skeletal muscle, the ratio of SH to S-S groups is higher than in the mixed denatured proteins of other tissues, with a single exception—the proteins of the crystalline lens. 2. The number of active SH groups in the proteins of minced muscle or in any of the protein fractions of muscle is only a fraction of the number found after the proteins have been treated with a denaturing agent. 3. The SH groups of the native proteins of muscle are activated by a rise in pH. 4. The relation between pH and number of active SH groups in the proteins of minced muscle and in the various protein fractions of muscle shows that little, if any, denatured protein is present in minced muscle.

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