scholarly journals The Isolation and Properties of Some Soluble Proteins From Wool VI. The Physicochemical Properties of Sgmkb2

1963 ◽  
Vol 16 (1) ◽  
pp. 252 ◽  
Author(s):  
JM Gillespie ◽  
BS Harrap
Keyword(s):  
Molecular Weight ◽  
No Reduction ◽  
Sedimentation Coefficient ◽  
Chain Structure ◽  
Optical Rotatory Dispersion ◽  
Random Coil ◽  
Merino Wool ◽  
Frictional Properties ◽  
Dispersion Data ◽  
End Group

The molecular weight of a high-sulphur protein (SCMKB2) from Merino wool has been determined by the Archibald technique and by light scattering, values of 22,600 and 22,100, respectively, being obtained. Optical rotatory dispersion data show that in aqueous solution the protein behaves as a random coil. This is consistent with the frictional properties of the molecule as deduced from its sedimentation coefficient and intrinsic viscosity. The protein appears to have one N-terminal arginyl end group; since it also contains two acyl groups per 22,000 molecular weight unit, the possibility of a multi�chain structure for the protein unit has been considered. However, no reduction in molecular weight could be achieved in any of several disaggregating solvents.

END GROUP AND SEDIMENTATION DATA ON FRAGMENTED HIGH MOLECULAR WEIGHT RIBONUCLEATES

1963 ◽  
Vol 41 (1) ◽  
pp. 1927-1941 ◽  
Author(s):  
B. G. Lane ◽  
J. Diemer ◽  
C. A. Blashko
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Snake Venom ◽  
Group Analysis ◽  
Sedimentation Coefficient ◽  
Snake Venom Phosphodiesterase ◽  
Ehrlich Ascites ◽  
Spontaneous Hydrolysis ◽  
Hydrolysis Of ◽  
End Group

A method for end group analysis of ribonucleate preparations using purified snake venom phosphodiesterase is described. Unusual difficulties encountered with the method are discussed. The technique is useful for detection of end groups resulting from enzymic and chemical fragmentation of high molecular weight ribonucleates. Preliminary studies indicate that the method has limited usefulness because of a spontaneous hydrolysis of ribonucleates which occurs under the conditions which are optimal for hydrolysis with snake venom phosphodiesterase (pH 9, in the presence of magnesium). Physicochemical studies have shown that the pronounced dependence of sedimentation coefficient on ionic strength which has been reported by other investigators is also observed with fragmented high molecular weight ribonucleates and with 16S + 24S ribonucleates of Ehrlich ascites cells. The changes of sedimentation rate are associated with configurational and aggregation effects.

Stability of acetylcholinesterase in guanidine hydrochloride solution

1981 ◽  
Vol 59 (7) ◽  
pp. 551-555 ◽  
Author(s):  
Faizan Ahmad
Keyword(s):  
Molecular Weight ◽  
Guanidine Hydrochloride ◽  
Sedimentation Coefficient ◽  
Conformational State ◽  
Random Coil ◽  
Aromatic Residues ◽  
Activity Measurements ◽  
Irreversible Unfolding ◽  
Hydrochloride Solution ◽  
Circular Dichroic

The irreversible unfolding of acetylcholinesterase (acetylcholine hydrolyase, EC 3.1.1.7) by guanidine hydrochloride was studied by difference spectral, circular dichroic, and enzyme activity measurements. At pH 7.0 and in 1.1 M denaturant solution, a conformational state in which enzyme is completely inactive was detected. It is identical to the native enzyme as far as sedimentation coefficient and molecular weight are concerned, but differs from the native molecule by a slight loss in secondary structure and by a small perturbation of aromatic residues. Acetylcholinesterase in concentrated guanidine hydrochloride solution containing β-mercaptoethanol dissociates and exists as a random coil of molecular weight 68 000.

Physicochemical and chemical studies on wheat embryo ribosomal proteins

1968 ◽  
Vol 46 (4) ◽  
pp. 373-380 ◽  
Author(s):  
Fred H. Wolfe ◽  
Cyril M. Kay
Keyword(s):  
Molecular Weight ◽  
Ribosomal Proteins ◽  
High Speed ◽  
Polyacrylamide Gel Electrophoresis ◽  
Average Molecular Weight ◽  
Optical Rotatory Dispersion ◽  
Random Coil ◽  
Wheat Embryo ◽  
Molecular Weights ◽  
A Value

The physical heterogeneity of unfractionated wheat embryo ribsomal proteins, prepared by the glacial acetic acid method of Waller and Harris, has been investigated in 8 M urea −10−3 M dithio-threitol solutions of low pH (4.5). Sedimentation–diffusion measurements resulted in a weight average molecular weight of 29 000 ± 2 500, with no obvious evidence of heterogeneity. High-speed membrane osmometry was employed to establish the number average molecular weight of this system as 24 500 ± 1 000. The disparity in molecular weight averages suggests some size heterogeneity, and statistical analysis based on the two average molecular weights resulted in a calculated range of molecular weights for wheat embryo ribosomal proteins from 15 000 to 34 000 a.m.u. Charge differences, reflecting presumably primary structure differences, also exist among the members of this class, since about 26 different bands were resolved on polyacrylamide gel electrophoresis. The weight intrinsic viscosity of the ribosomal proteins in 8 M urea solutions was established as 0.273 dl/g, a value considerably larger than most globular proteins, suggesting that a major portion of their polypeptide chains are unfolded in this solvent. This conclusion was substantiated by optical rotatory dispersion measurements on this system, which resulted in a dispersion constant, λc, of 213 m μ, a value typical of that of the random coil. Amino acid and N-terminal analyses are also reported for this system, and comparisons of both chemical and physicochemical parameters are made with ribosomal proteins of other sources.

END GROUP AND SEDIMENTATION DATA ON FRAGMENTED HIGH MOLECULAR WEIGHT RIBONUCLEATES

1963 ◽  
Vol 41 (9) ◽  
pp. 1927-1941 ◽  
Author(s):  
B. G. Lane ◽  
J. Diemer ◽  
C. A. Blashko
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Snake Venom ◽  
Group Analysis ◽  
Sedimentation Coefficient ◽  
Snake Venom Phosphodiesterase ◽  
Ehrlich Ascites ◽  
Spontaneous Hydrolysis ◽  
Hydrolysis Of ◽  
End Group

A method for end group analysis of ribonucleate preparations using purified snake venom phosphodiesterase is described. Unusual difficulties encountered with the method are discussed. The technique is useful for detection of end groups resulting from enzymic and chemical fragmentation of high molecular weight ribonucleates. Preliminary studies indicate that the method has limited usefulness because of a spontaneous hydrolysis of ribonucleates which occurs under the conditions which are optimal for hydrolysis with snake venom phosphodiesterase (pH 9, in the presence of magnesium). Physicochemical studies have shown that the pronounced dependence of sedimentation coefficient on ionic strength which has been reported by other investigators is also observed with fragmented high molecular weight ribonucleates and with 16S + 24S ribonucleates of Ehrlich ascites cells. The changes of sedimentation rate are associated with configurational and aggregation effects.

PHYSICOCHEMICAL STUDIES OF ALKALI LIGNINS: III. SIZE AND SHAPE OF THE MACROMOLECULE

1960 ◽  
Vol 38 (2) ◽  
pp. 270-279 ◽  
Author(s):  
P. R. Gupta ◽  
D. A. I. Goring
Keyword(s):  
Molecular Weight ◽  
Sedimentation Coefficient ◽  
Random Coil ◽  
Alkali Lignin ◽  
Molecular Weights ◽  
A Value ◽  
Huggins Constant ◽  
Physicochemical Studies ◽  
Lignin Macromolecule ◽  
Very High

Light-scattering measurements were made on the alkali lignin fractions described in a previous paper. The range of molecular weights found was from 50,000 to 48 × 106. The usual logarithmic graph of intrinsic viscosity and molecular weight was linear and gave a value of 0.32 for the exponent. From the logarithmic sedimentation coefficient – molecular weight relationship, the exponent was found as 0.52. Flory's hydrodynamic parameter [Formula: see text] was 2.3 × 106. These results suggested that the configuration of the alkali lignin macromolecule conformed to a structure between that of a random coil and an Einstein's sphere impenetrable to solvent. The branching parameter, g, introduced by Zimm and Stockmayer, decreased with an increase in molecular weight as expected. Most of the values of Huggins' constant, k′,were between 1 and 2 which indicated a compact particle. A marked increase in k′ was noted for fractions of low or very high molecular weight. The significance of the data is discussed and a model tentatively suggested for the macromolecule.

Helix to coil transition in poly-L-amino acids. II. N.M.R. study of model compounds and Poly-γ-benzyl-L-glutamate

1969 ◽  
Vol 22 (2) ◽  
pp. 357 ◽  
Author(s):  
JH Bradbury ◽  
MD Fenn
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Magnetic Resonance ◽  
Amide Group ◽  
Dichloroacetic Acid ◽  
Model Systems ◽  
Optical Rotatory Dispersion ◽  
Random Coil ◽  
Low Molecular Weight ◽  
Coil Transition

The proton magnetic resonance spectroscopy of simple amides and poly-L- amino acids has been investigated with particular reference to the question of charging of the amide group in strong acids. It is found that the downfield chemical shift of the α-CH resonance of poly-γ- benzyl-L-glutamate (PBG) which accompanies the helix to coil transition can be conveniently divided into two parts on the basis of experiments with model systems. The first is due to the collapse of the helix to an uncharged random coil and the second represents the charging of the amide groups of the random coil. For PBG samples of low molecular weight, two α-CH resonances are observed due to residues in helical (uncharged) and random-coil (charged) forms. The rate of exchange between them is of the order of 400 sec-1. The proton resonances of the NH proton, COOH proton of the acid, and α-CH proton of dichloroacetic acid (DCA) are shown to be less useful than the α-CH proton. A critical evaluation has been made of all the evidence relevant to the charging of the amide group of polypeptides in mixtures of non-interacting solvents and organic acids e.g. trifluoroacetic acid (TFA) and DCA. It is concluded that viscosity, infrared, dielectric constant, electric birefringence, and conductivity studies give overwhelming support to the concept of charging. Nuclear magnetic resonance, circular dichroism, and optical rotatory dispersion are less sensitive indicators of small amounts of charging, and hence studies should be made with samples of low molecular weight (where there is a greater fractional degree of charging). Such studies made here by n.m.r. methods give strong support for charging. The features of the flexible helix model first proposed in Part I are delineated. It consists of helical segments separated by short, charged random-coil breaks at both ends and in the interior of the molecule. Although elaborated in some detail for the case of PBG, it is likely to occur quite generally for those polypeptides which are soluble in organic solvents and undergo the helix to coil transition.

Rapid Isolation of High Molecular Weight Urokinase from Native Human Urine

1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Human Urine ◽  
Gel Filtration ◽  
Chain Structure ◽  
The Other ◽  
Single Chain ◽  
Apparent Homogeneity ◽  
Sequential Adsorption

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

Investigating the Rheological Properties and Heat Stability of Polyarylsulphone Sulphides of Domestic Grades

2017 ◽  
Vol 44 (1) ◽  
pp. 23-26
Author(s):  
A.B. Baranov ◽  
I.D. Simonov-Emel'yanov ◽  
T.I. Andreeva ◽  
T.N. Prudskova ◽  
V.I. Sazikov
Keyword(s):  
Molecular Weight ◽  
Heat Stability ◽  
Chain Structure ◽  
Low Flow ◽  
Processing Temperature ◽  
Rheological Characteristics ◽  
Melt Viscosity ◽  
Full Curve ◽  
Temperature Range ◽  
Service Characteristics

The rheological characteristics of melts of polyarylsulphone sulphides of domestic grades were investigated in the temperature range 240–360°C. Full curves of heat stability were obtained, and formulae were proposed for their description. Polyarylsulphone sulphides (PSPSs) are heat-resistant polymers of structural designation of the polysulphone (PSP) class, the domestic production technology of which was developed at OAO “Institut plastmass”, which makes it possible to carry out the production of a wide grade range of PSP of different polymer chain structure and molecular weight. The main problem in the processing of PSPSs is their high melt viscosity and fairly low flow. Increase in the processing temperature lowers their melt viscosity, but there is then the danger of thermooxidative degradation of the polymer and consequently of deterioration in the service characteristics and appearance of articles. The aim of this work was to investigate the rheological characteristics and to obtain the full curve of heat stability for domestic grades of PSPSs and PSP of different molecular weight in a wide processing temperature range.

Effect on Polymer Chain Structure Caused by the Molar Fraction of 4-Hydroxybutyrate in Poly(3-hydroxybutyrate- co -4-hydroxybutyrate)

2012 ◽  
Vol 602-604 ◽  
pp. 776-780
Author(s):  
Zhi Qiang Li ◽  
Mei Li ◽  
Wei Jia Fan
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Polymer Chain ◽  
Molar Fraction ◽  
Chain Structure ◽  
The Other ◽  
Mean Square ◽  
Polarizing Microscope ◽  
Other Hand ◽  
The Mean

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)copolymer [P(3HB-co-4HB)] is a kind of biodegradable high molecular polymer produced by bioaccumulation. Because of the good biodegradability and biocompatibility, P(3HB-co-4HB)s have attracted wide attention . At first, the intrinsic viscosity[η] in good solvent of P(3HB-co-4HB) s with varying contents of 4HB was investigated in different temperature. Second, observed the changes of crystallization gathered state caused by the varying contents of 4HB by polarizing microscope. The results show that to the P(3HB-co-4HB)s in same molecular weight, the intrinsic viscosity[η] in good solvent barely changes when the mole fractions of 4HB increase. On the other hand, the mean square end to end distances[0] of macromolecular flexible chains increase with the mole fractions of 4HB. At the same time, the states of aggregation change from spherulites to dendrites. In this investigation, we discuss the reasons of the differences in depth.

scholarly journals Multiplicity of Active-Site in Heterogeneous Ziegler-Natta Catalyst and Its Correlation with Polymer Microstructure

1970 ◽  
Vol 46 (4) ◽  
pp. 487-494
Author(s):  
ATM Kamrul Hasan
Keyword(s):  
Molecular Weight ◽  
Computer Simulation ◽  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Chain Structure ◽  
Surface Complexes ◽  
Polymer Microstructure ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

Multiplicity of active-site in heterogeneous Ziegler-Natta catalysts and its correlation with polymer microstructure was studied through the surface structure analysis of catalyst by computer simulation of X-ray Photoelectron Spectroscopy (XPS) data and microstructure investigation of polypropylene chains based on the deconvolution of the molecular weight distribution curves by multiple Flory most probable distributions using Gel Permeation Chromatography (GPC) method. The number and relative intensities of these peaks were found correlated to the distribution of multiple active sites. In this investigation, four individual categories of active sites were identified, each of which yields polypropylene with unique properties of molecular weight and chain structure different from other active sites. The reason of the multiplicity of active sites was determined by the presence of different locations of surface titanium species coordinated with other surface atoms or molecules. These different surface complexes of active species determine the multiple active site nature of catalyst which replicates the microtacticity, molecular weight and chain microstructure distribution of polymer. Keywords: Ziegler-Natta catalyst; Multiple active sites; Flory components; Computer simulation; Deconvolution; MWD. DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9596 BJSIR 2011; 46(4): 487-494

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