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 ANTIGENIC PROPERTIES OF NATIVE AND REGENERATED HORSE SERUM ALBUMIN

1943 ◽  
Vol 78 (1) ◽  
pp. 1-8 ◽  
Author(s):  
John O. Erickson ◽  
Hans Neurath
Keyword(s):  
Serum Albumin ◽  
Protein Denaturation ◽  
Horse Serum ◽  
Native State ◽  
Immunological Activity ◽  
Denatured Protein ◽  
Antigenic Activity ◽  
Antigenic Properties ◽  
The Mean ◽  
Physical And Chemical

Comparative immunological measurements have been carried out on crystalline horse serum albumin in the native state and after regeneration from 8 M urea solutions. The mean antigenic activity of the regenerated protein has been found to be less than 10 per cent of that of the native, whereas both antigens proved to be immunologically equivalent. The problem of the relation between protein denaturation and immunological activity has been considered and discussed on the basis of known physical and chemical differences between native and denatured protein.

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 Insights into the role of protein molecule size and structure on interfacial properties using designed sequences

2013 ◽  
Vol 10 (80) ◽  
pp. 20120987 ◽  
Author(s):  
Mirjana Dimitrijev Dwyer ◽  
Lizhong He ◽  
Michael James ◽  
Andrew Nelson ◽  
Anton P. J. Middelberg
Keyword(s):  
Stress Response ◽  
Molecular Size ◽  
Interfacial Properties ◽  
Protein Molecule ◽  
Mixed System ◽  
Free Energy Of Adsorption ◽  
Air Water Interface ◽  
A Chain ◽  
Size And Structure

Mixtures of a large, structured protein with a smaller, unstructured component are inherently complex and hard to characterize at interfaces, leading to difficulties in understanding their interfacial behaviours and, therefore, formulation optimization. Here, we investigated interfacial properties of such a mixed system. Simplicity was achieved using designed sequences in which chemical differences had been eliminated to isolate the effect of molecular size and structure, namely a short unstructured peptide (DAMP1) and its longer structured protein concatamer (DAMP4). Interfacial tension measurements suggested that the size and bulk structuring of the larger molecule led to much slower adsorption kinetics. Neutron reflectometry at equilibrium revealed that both molecules adsorbed as a monolayer to the air–water interface (indicating unfolding of DAMP4 to give a chain of four connected DAMP1 molecules), with a concentration ratio equal to that in the bulk. This suggests the overall free energy of adsorption is equal despite differences in size and bulk structure. At small interfacial extensional strains, only molecule packing influenced the stress response. At larger strains, the effect of size became apparent, with DAMP4 registering a higher stress response and interfacial elasticity. When both components were present at the interface, most stress-dissipating movement was achieved by DAMP1. This work thus provides insights into the role of proteins' molecular size and structure on their interfacial properties, and the designed sequences introduced here can serve as effective tools for interfacial studies of proteins and polymers.

In Vitro Attenuation of Thermal-Induced Protein Denaturation by Aerial Parts of Artemisia scoparia

2014 ◽  
Vol 20 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Murad Ali Khan ◽  
Haroon Khan ◽  
Shafiq Ahmad Tariq ◽  
Samreen Pervez
Keyword(s):  
Crude Extract ◽  
Protein Denaturation ◽  
Total Flavonoid ◽  
Significant Activity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Aqueous Fraction ◽  
Denatured Protein ◽  
Aerial Parts ◽  
Artemisia Scoparia

The goal of this study was to explore the aerial parts of Artemisia scoparia (crude extract, total flavonoid contents, and aqueous fraction) for protein denaturation potential. The crude extract provoked marked attenuation of thermal-induced denatured protein in a concentration-dependent manner with maximum inhibition of 54.05 μg/mL at 500 μg/mL and IC50 of 449.66 μg/mL. When total flavonoid contents were studied, it illustrated most dominant activity concentration dependently with maximum amelioration of 62.16 μg/mL at 500 μg/mL and IC50 of 378.35 μg/mL. The aqueous fraction also exhibited significant activity with maximum of 56.75% inhibition at 500 μg/mL and IC50 of 445.10 μg/mL. It can be concluded on the basis of the results that the crude extract, flavonoid contents, and aqueous fraction of the plant possessed significant inhibition on thermal-induced denatured protein.

scholarly journals Batch Production of High-Quality Graphene Grids for Cryo-EM: Cryo-EM Structure of Methylococcus capsulatus Soluble Methane Monooxygenase Hydroxylase

2021 ◽  
Author(s):  
Eungjin Ahn ◽  
byungchul Kim ◽  
uhn-soo Cho
Keyword(s):  
Protein Denaturation ◽  
Methane Monooxygenase ◽  
Atomic Layer ◽  
Water Interface ◽  
Methylococcus Capsulatus ◽  
Force Microscopy ◽  
Voltage Electron ◽  
Soluble Methane Monooxygenase ◽  
Air Water Interface ◽  
Scanning Em

Cryogenic electron microscopy (cryo-EM) has become a widely used tool for determining protein structure. Despite recent advances in instruments and algorithms, sample preparation remains a major bottleneck for several reasons, including protein denaturation at the air/water interface and the presence of preferred orientations and nonuniform ice layers. Graphene, a two-dimensional allotrope of carbon consisting of a single atomic layer, has recently attracted attention as a near-ideal support film for cryo-EM that can overcome these challenges because of its superior properties, including mechanical strength and electrical conductivity. Graphene minimizes background noise and provides a stable platform for specimens under a high-voltage electron beam and cryogenic conditions. Here, we introduce a reliable, easily implemented, and reproducible method of producing 36 graphene-coated grids at once within 1.5 days. The quality of the graphene grids was assessed using various tools such as scanning EM, Raman spectroscopy, and atomic force microscopy. To demonstrate their practical application, we determined the cryo-EM structure of Methylococcus capsulatus soluble methane monooxygenase hydroxylase (sMMOH) at resolutions of 2.9 and 2.4 angstrom using Quantifoil and graphene-coated grids, respectively. We found that the graphene-coated grid has several advantages; for example, it requires less protein, enables easy control of the ice thickness, and prevents pro-tein denaturation at the air/water interface. By comparing the cryo-EM structure of sMMOH with its crystal structure, we revealed subtle yet significant geometrical differences at the non-heme di-iron center, which may better indicate the active site configuration of sMMOH in the resting/oxidized state.

scholarly journals THE STAGES OF THE PEPTIC HYDROLYSIS OF EGG ALBUMIN

1927 ◽  
Vol 10 (3) ◽  
pp. 437-450 ◽  
Author(s):  
Jennie McFarlane ◽  
Violet E. Dunbar ◽  
Henry Borsook ◽  
Hardolph Wasteneys
Keyword(s):  
Protein Molecule ◽  
Total N ◽  
Egg Albumin ◽  
Hydrolysis Of

1. Most of the products of the peptic hydrolysis of albumin, about 85 per cent of the total N, are primary in the sense that they arise directly from the protein molecule, and undergo no further hydrolysis. 2. A slow secondary hydrolysis, involving about 15 per cent of the total N, occurs in the proteose and simpler fractions primarily split off. 3. Acid metaprotein in peptic hydrolysis arises as a result of the action of acid. It is not an essential stage in the hydrolysis of undenatured albumin. 4. Acid metaprotein is hydrolyzed by pepsin more slowly under comparable conditions than undenatured albumin.

scholarly journals Ketoprofen-Based Ionic Liquids: Synthesis and Interactions with Bovine Serum Albumin

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 90 ◽  
Author(s):  
Paula Ossowicz ◽  
Proletina Kardaleva ◽  
Maya Guncheva ◽  
Joanna Klebeko ◽  
Ewelina Świątek ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Binding Constants ◽  
Protein Molecule ◽  
Binding Mode ◽  
Pharmaceutical Ingredients ◽  
System A ◽  
Static Mechanism

The development of ionic liquids based on active pharmaceutical ingredients (API-ILs) is a possible solution to some of the problems of solid and/or hydrophobic drugs such as low solubility and bioavailability, polymorphism and an alternative route of administration could be suggested as compared to the classical drug. Here, we report for the first time the synthesis and detailed characterization of a series of ILs containing a cation amino acid esters and anion ketoprofen (KETO-ILs). The affinity and the binding mode of the KETO-ILs to bovine serum albumin (BSA) were assessed using fluorescence spectroscopy. All compounds bind in a distance not longer than 6.14 nm to the BSA fluorophores. The estimated binding constants (KA) are in order of 105 L mol−1, which is indicative of strong drug or IL-BSA interactions. With respect to the ketoprofen-BSA system, a stronger affinity of the ILs containing l-LeuOEt, l-ValOBu, and l-ValOEt cation towards BSA is clearly seen. Fourier transformed infrared spectroscopy experiments have shown that all studied compounds induced a rearrangement of the protein molecule upon binding, which is consistent with the suggested static mechanism of BSA fluorescence quenching and formation of complexes between BSA and the drugs. All tested compounds were safe for macrophages.

scholarly journals Microwave-assisted synthesis, computational studies and antibacterial/ anti-inflammatory activities of compounds based on coumarin-pyrazole hybrid

2018 ◽  
Vol 5 (5) ◽  
pp. 172435 ◽  
Author(s):  
Rakesh R. Chavan ◽  
Kallappa M. Hosamani
Keyword(s):  
Schiff Base ◽  
Protein Denaturation ◽  
Docking Study ◽  
High Yield ◽  
Diffusion Method ◽  
Microwave Assisted Synthesis ◽  
Spectroscopic Techniques ◽  
Molecular Docking Study ◽  
Egg Albumin ◽  
Anti Inflammatory

An efficient, high-yield and rapid synthesis of (E)-1,5-dimethyl-4-((2-((substituted-2-oxo-2H-chromen-4-yl)methoxy)naphthalen-1-yl)methyleneamino)-2-phenyl-1,2-dihydropyrazol-3-one derivatives (3a–3i) containing Schiff base structures under microwave-irradiation has been described. Schiff base is a potential target to discover anti-inflammatory chemotherapeutics, material science, catalysis and molecular magnetism. All the newly synthesized compounds (3a–3i) have been characterized by elemental analysis and spectroscopic techniques. The synthesized compounds (3a–3i) were evaluated for their antibacterial activity by agar-well diffusion method and anti-inflammatory activity by egg albumin denaturation method. The compounds (3e) and (3i) exhibit antibacterial effect with minimum inhibitory concentration (MIC) 0.78 µg ml −1 and MIC 1.562 µg ml −1 against Gram-positive Staphylococcus aureus bacterial strain compared with standard ciprofloxacin drug (MIC 6.25 µg ml −1 ). The compounds (3c) and (3f) exhibited an inhibition of heat-induced protein denaturation at the concentration (31.25 µg ml −1 ) as 53.65% and 67.27%, respectively, and these compounds are more active than standard aceclofenac drug (5.50%). Molecular docking study has been performed for all the synthesized compounds with S. aureus dihydropteroate synthetase and results obtained are quite promising.

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