A diffusion NMR method for the prediction of the weight-average molecular weight of globular proteins in aqueous media of different viscosities

2019 ◽  
Vol 11 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Francisco M. Arrabal-Campos ◽  
Luis M. Aguilera-Sáez ◽  
Ignacio Fernández
Keyword(s):  
Average Molecular Weight ◽  
Aqueous Media ◽  
Globular Proteins ◽  
Weight Average Molecular Weight ◽  
Solvent Viscosity ◽  
Molecular Weights ◽  
Nmr Method ◽  
Diffusion Nmr ◽  
Successful Prediction ◽  
First Time

We have introduced for the first time, a non-viscosity dependent universal calibration curve (UCC) for the successful prediction of the weight-average molecular weights of globular proteins in the range of 8.5–66.2 kDa with no dependence on the solvent viscosity.

SIZE, STABILITY, AND HETEROGENEITY OF APURINIC ACID

1956 ◽  
Vol 34 (6) ◽  
pp. 1107-1117 ◽  
Author(s):  
G. C. Wood ◽  
David B. Smith
Keyword(s):  
Molecular Weight ◽  
Nucleic Acid ◽  
Acid Treatment ◽  
Average Molecular Weight ◽  
Weight Average Molecular Weight ◽  
Molecular Weights ◽  
Size Stability ◽  
Mild Acid

Apurinic acid prepared by mild acid treatment of sodium desoxyribonucleate and of fractions of sodium desoxyribonucleate was sufficiently stable to permit estimations of molecular weight and polydispersity. Apurinic acid from unfractionated desoxyribonucleate had a weight-average molecular weight of 25,000 and was very polydisperse. Preparations from fractionated desoxyribonucleate representing about half the original nucleic acid were much less polydisperse and had molecular weights of about 10,000.

SIZE, STABILITY, AND HETEROGENEITY OF APURINIC ACID

1956 ◽  
Vol 34 (1) ◽  
pp. 1107-1117
Author(s):  
G. C. Wood ◽  
David B. Smith
Keyword(s):  
Molecular Weight ◽  
Nucleic Acid ◽  
Acid Treatment ◽  
Average Molecular Weight ◽  
Weight Average Molecular Weight ◽  
Molecular Weights ◽  
Size Stability ◽  
Mild Acid

Apurinic acid prepared by mild acid treatment of sodium desoxyribonucleate and of fractions of sodium desoxyribonucleate was sufficiently stable to permit estimations of molecular weight and polydispersity. Apurinic acid from unfractionated desoxyribonucleate had a weight-average molecular weight of 25,000 and was very polydisperse. Preparations from fractionated desoxyribonucleate representing about half the original nucleic acid were much less polydisperse and had molecular weights of about 10,000.

scholarly journals The molecular weight of, and evidence for two types of subunits in, the molybdenum-iron protein of Azotobacter vinelandii nitrogenase

1977 ◽  
Vol 163 (3) ◽  
pp. 427-432 ◽  
Author(s):  
R H Swisher ◽  
M L Landt ◽  
F J Reithel
Keyword(s):  
Molecular Weight ◽  
Azotobacter Vinelandii ◽  
Average Molecular Weight ◽  
Amino Acid Content ◽  
Sedimentation Equilibrium ◽  
Weight Average Molecular Weight ◽  
Molybdenum Iron Protein ◽  
Iron Protein ◽  
Molecular Weights ◽  
Fe Protein

The weight-average molecular weight of the Mo-Fe protein isolated from Azotobacter vinelandii has been determined by sedimentation-equilibrium techniques. In buffer, the value is 245000+/-5000; in 8M-urea, the value is 61000+/-1000. The protein was separated into two components by chromatography on CM-cellulose in 7M-urea, pH 4.5. These components have similar molecular weights but were shown to differ in charge, amino acid content and arginine-containing peptides. It is proposed that the tetramer has the subunit composition (nalpha2nbeta2).

Molecular weight prediction with no dependence on solvent viscosity. A quantitative pulse field gradient diffusion NMR approach

2016 ◽  
Vol 7 (26) ◽  
pp. 4326-4329 ◽  
Author(s):  
Francisco M. Arrabal-Campos ◽  
Pascual Oña-Burgos ◽  
Ignacio Fernández
Keyword(s):  
Molecular Weight ◽  
Pulse Field ◽  
Pulse Field Gradient ◽  
Fast Determination ◽  
Solvent Viscosity ◽  
Molecular Weights ◽  
Diffusion Nmr ◽  
Gradient Diffusion ◽  
Weight Prediction

To progress on the practical issues of molecular weight prediction via diffusion NMR, the first log(Dη) vs. log(Mw) calibration curve is provided, allowing the easy and fast determination of weight-average molecular weights with no matter of the solvent used.

scholarly journals Use of Rubber Process Analyzer for Characterizing the Molecular Weight Parameters of Natural Rubber

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Tianming Gao ◽  
Ruihong Xie ◽  
Linghong Zhang ◽  
Hongxing Gui ◽  
Maofang Huang
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Milling Time ◽  
Laser Light ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Sweep Frequency ◽  
Weight Average Molecular Weight ◽  
Molecular Weights ◽  
Strain Sweep

The aim of this work is to introduce a simple and rapid method for characterizing the molecular weight parameters and other molecular structure parameters of natural rubber (NR) using a rubber process analyzer (RPA). In this work, NR of different molecular weights was prepared by milling. Molecular weight parameters were measured by gel permeation chromatography coupled with laser light scattering (GPC-LLS) for comparison with RPA results. It was verified that increasing of milling time leads to a decrease of the number-average molecular weight (M-n), weight-average molecular weight (M-w), and molecular weight distribution (MWD). The dynamic and rheological properties were evaluated on RPA by tests of strain sweep, frequency sweep, and stress relaxation. These results were used to characterize the average molecular weight, MWD, and viscosity of NR and were found to agree with those from GPC-LLS. This convenient and rapid technology for characterizing NR molecular weight parameters would be especially useful in the elastomer industry.

INFLUENCE OF METHANOL ON VISCOSITY AND LIGHT SCATTERING PROPERTIES OF DEXTRAN SOLUTIONS

1956 ◽  
Vol 34 (4) ◽  
pp. 445-450 ◽  
Author(s):  
W. Donald Graham ◽  
Odette Patry ◽  
E. Helen Jackman
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Intrinsic Viscosity ◽  
Marked Effect ◽  
Average Molecular Weight ◽  
Alcohol Concentration ◽  
Methanol Concentration ◽  
Weight Average Molecular Weight ◽  
Molecular Weights ◽  
Apparent Weight

Failure to consider the presence of up to 16% by volume of methanol in solutions of dextran fractions had a very marked effect on apparent intrinsic viscosity determinations (the term apparent signifies that measurements were made assuming that the solvent was water only). Unless methanol were removed or otherwise taken into account, high erroneous results were obtained. Apparent weight average molecular weights determined by light scattering were not significantly affected at these alcohol concentrations. The relations found over the range 0 to 16% methanol for dextran samples with weight average molecular weights of 265,000, 155,000, and 72,000 held for the latter sample up to 44% methanol. In the higher range of alcohol concentration the apparent weight average molecular weight was depressed. The true intrinsic viscosity of dextran solutions decreased as methanol concentration was increased.

Structure of the exudate gum from Meryta sinclairii

2020 ◽  
Author(s):  
Ian Sims ◽  
Richard Furneaux
Keyword(s):  
Average Molecular Weight ◽  
Gum Arabic ◽  
Arabinogalactan Protein ◽  
Weight Average Molecular Weight ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Linkage Analyses ◽  
Yariv Reagent ◽  
Native Tree ◽  
High Level

A gum that exudes from the wounded trunk of the New Zealand native tree Meryta sinclairii has been isolated. The gum was completely precipitated by the β-glucosyl Yariv reagent and was thus determined to be an arabinogalactan-protein (AGP). It contained >95% w/w carbohydrate and only 2% w/w protein with a high level of hydroxyproline. SEC-MALLS showed that the gum had a weight-average molecular weight of 4.45×106Da compared with 6.02×105Da for gum arabic. Constituent sugar and linkage analyses were consistent with polymers comprised of a highly branched backbone of 1,3-linked galactopyranosyl (Galp) residues, with side-chains made up of arabinofuranose- (Araf) containing oligosaccharides, terminated variously by rhamnopyranosyl (Rhap), arabinopyranosyl (Arap), Galp and glucuronopyranosyl (GlcpA) residues. Analysis by one-dimensional and two-dimensional 1H and 13C NMR experiments confirmed the linkage analyses. The structure of the gum is discussed in comparison with the structure of gum arabic and other AGPs. © 2003 Elsevier Science Ltd. All rights reserved.

Molecular, rheological and physicochemical characterisation of puka gum, an arabinogalactan-protein extracted from the Meryta sinclairii tree

2020 ◽  
Author(s):  
MSM Wee ◽  
Ian Sims ◽  
KKT Goh ◽  
L Matia-Merino
Keyword(s):  
Hydrodynamic Radius ◽  
Average Molecular Weight ◽  
Gum Arabic ◽  
Water Soluble ◽  
Arabinogalactan Protein ◽  
Type Ii ◽  
Weight Average Molecular Weight ◽  
Soluble Polysaccharide ◽  
Physicochemical Characterisation ◽  
Increasing Temperature

© 2019 Elsevier Ltd A water-soluble polysaccharide (type II arabinogalactan-protein) extracted from the gum exudate of the native New Zealand puka tree (Meryta sinclairii), was characterised for its molecular, rheological and physicochemical properties. In 0.1 M NaCl, the weight average molecular weight (Mw) of puka gum is 5.9 × 106 Da with an RMS radius of 56 nm and z-average hydrodynamic radius of 79 nm. The intrinsic viscosity of the polysaccharide is 57 ml/g with a coil overlap concentration 15% w/w. Together, the shape factor, p, of 0.70 (exponent of RMS radius vs. hydrodynamic radius), Smidsrød-Haug's stiffness parameter B of 0.031 and Mark-Houwink exponent α of 0.375 indicate that the polysaccharide adopts a spherical conformation in solution, similar to gum arabic. The pKa is 1.8. The polysaccharide exhibits a Newtonian to shear-thinning behaviour from 0.2 to 25% w/w. Viscosity of the polysaccharide (1 s−1) decreases with decreasing concentration, increasing temperature, ionic strength, and at acidic pH.

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