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Se Pu = Chinese Journal of... Oct 2021Low-molecular-weight glycoproteins (LMW-GPs) are considered promising candidates for disease biomarker discovery. Selective sorbents are essential for the extraction and...
Low-molecular-weight glycoproteins (LMW-GPs) are considered promising candidates for disease biomarker discovery. Selective sorbents are essential for the extraction and enrichment of this class of compounds. Boronate affinity chromatography is a unique separation mode in liquid chromatography. It enables the selective separation and isolation of -diol-containing compounds such as glycoproteins and saccharides. Recent years have witnessed the rapid development of boronate affinity materials, particularly for use as selective sorbents in proteomics and metabolomics. However, studies are scarce on the specific design of such materials for the selective extraction of LMW-GPs. Herein, we present multifunctional magnetic nanoparticles (MNPs) for selectively harvesting LWM-GPs. The multifunctional MNPs were rationally designed and prepared by wrapping magnetic core nanoparticles with a phenylboronic acid-grafted poly(acrylic acid) (PAA) network. In addition to fulfilling the primary function of conventional MNPs in magnetic separation, multifunctional MNPs can offer three pre-determined advanced functions: 1) the size-restriction effect, which enables the elimination of the interference of high-molecular-weight proteins and other species; 2) the selective extraction of LMW-GPs; and 3) protection of the harvested LMW-GPs against degradation and contamination. The multifunctional MNPs enable selective extraction due to the affinity of the boronic acid ligand to the -diol moieties of the glycoproteins. The size-restriction effect and protection function depend on the polymer network on the surface of the MNPs, which allows the selective passage of low-molecular-weight molecules. Transmission electron microscopy (TEM) characterization showed that the MNPs were well-shaped nanoparticles, with a diameter of approximately 60 nm. The size-restriction effect was first predicted by a thermogravimetric analysis-based theoretical calculation, where for MNPs prepared using PAA with an average molecular weight of 240 kDa, the estimated pore size of the network was 0.9 nm. The boronate affinity and size-exclusion effect were verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and capillary zone electrophoresis (CZE). To investigate the dependence of the selectivity of the MNPs to LMW-GPs in a complex environment and the size-restriction threshold for the PAA chain length, nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) was performed to analyze the molecular mass of fragments harvested by the MNPs from the tryptic digest of horseradish peroxidase (HRP, a typical glycoprotein). The polymer chain length or the molecular weight of the PAA used played a critical role in determining the molecular weight thresholds of proteins above which the size exclusion effect will occur. The threshold values were found to be 5.0, 9.3, 4.1, 5.1, and 2.7 kDa for MNPs prepared using PAA with average molecular weights of 2, 5, 15, 100, and 240 kDa, respectively. This dependence enabled adjustment of the threshold value for inducing the size-exclusion effect of the multifunctional MNPs by changing the PAA chain length. The multifunctional MNPs can be further developed into promising nanoprobes for selectively harvesting not only LMW-GPs, but also other -diol-containing biomolecules of biological importance, such as nucleosides and glycans. Thus, the material preparation strategy reported herein offers new insights for the rational design and synthesis of multifunctional-affinity sorbents to selectively extract target compounds from a complex sample matrix.
Topics: Glycoproteins; Magnetics; Magnetite Nanoparticles; Molecular Weight; Tandem Mass Spectrometry
PubMed: 34505432
DOI: 10.3724/SP.J.1123.2021.07019 -
Macromolecular Rapid Communications Mar 2021Effects of molecular weight of methylphenyl-containing vinylsiloxy-functionalized terpolysiloxanes on their UV-activated crosslinking by hydrosilylation at room...
Effect of Molecular Weight of Methylphenylsiloxy-Containing Vinyl-Functionalized Terpolysiloxanes on Their UV-Activated Crosslinking by Hydrosilylation and Mechanical Properties of Crosslinked Elastomers.
Effects of molecular weight of methylphenyl-containing vinylsiloxy-functionalized terpolysiloxanes on their UV-activated crosslinking by hydrosilylation at room temperature in air, shelf life stability of "all-in-one" pastes prepared from them for additive manufacturing, and mechanical properties of the resulting crosslinked elastomers, are investigated. It is found that while rheology of pastes containing base polymers, trimethylsilylated silica fillers, and thixotropic additives is not significantly affected by the base polymer molecular weight but is dominated by the filler concentration, the pastes based on higher molecular weight polymers exhibit faster crosslinking (corresponding to higher catalyst turnover numbers) and their crosslinked elastomers show transient strain-induced crystallization. The latter appears in networks from terpolymers with degrees of polymerization (DP) of 240 and above (corresponding to about one half of the critical polydimethylsiloxane chain length for entanglement formation of DP = 460), within the temperature range of -80 to -30 °C, characteristic for polydimethylsiloxane melting transition. It is believed that this is the first time an observation of this chain length effect is reported for polysiloxane elastomers and that the properties reported herein can be expected to have major implications on the application potential of these polymers in both additive manufacturing and performance of their elastomers at sub-ambient temperatures.
Topics: Elastomers; Molecular Weight; Polymerization; Polymers; Rheology
PubMed: 33502036
DOI: 10.1002/marc.202000692 -
Nature Dec 1947
Topics: Amylases; Molecular Weight; alpha-Amylases
PubMed: 18917307
DOI: 10.1038/160899a0 -
The Analyst Jul 2015We trap a set of molecular weight standard globular proteins using a double nanohole optical trap. The root mean squared variation of the trapping laser transmission...
We trap a set of molecular weight standard globular proteins using a double nanohole optical trap. The root mean squared variation of the trapping laser transmission intensity gives a linear dependence with the molecular weight, showing the potential for analysis of globular proteins. The characteristic time of the autocorrelation of the trapping laser intensity variations scales with a -2/3 power dependence with the volume of the particle. A hydrodynamic laser tweezer model is used to explain these dependencies. Since this is a single particle technique that operates in solution and can be used to isolate an individual particle, we believe that it provides an interesting alternative to existing analysis methods and shows promise to expand the capabilities of protein related studies to the single particle level.
Topics: Molecular Weight; Nanotechnology; Optical Tweezers; Proteins
PubMed: 25739349
DOI: 10.1039/c5an00026b -
Analytica Chimica Acta Nov 2020Solvent-based protein precipitation provides exceptional recovery, particularly when the ionic strength of the solution is controlled. While precipitation is ideally...
Solvent-based protein precipitation provides exceptional recovery, particularly when the ionic strength of the solution is controlled. While precipitation is ideally suited for intact protein purification ahead of mass-spectrometry, low molecular weight (LMW) proteins and peptides are considered less susceptible to aggregation in organic solvent. As the combination of salt and organic solvent (i.e. acetone) has yet to be exploited to precipitate LMW proteins, we herein determine the low mass limit for solvent-based protein precipitation. We establish optimized conditions for high recovery precipitation of LMW proteins and peptides. Our results demonstrate a strong dependence on the type of salt to recover LMW components from complex mixtures. Inclusion of 100 mM ZnSO with 97% acetone provides near quantitative recovery of all peptides down to 2 kDa, and continues to exceed 90% yield for peptides at a molecular weight of 1 kDa. A detailed characterization of the precipitated peptides resulting from trypsin and pepsin digestion of complex systems is provided by bottom-up mass spectrometry.
Topics: Acetone; Mass Spectrometry; Molecular Weight; Peptides; Trypsin
PubMed: 33161983
DOI: 10.1016/j.aca.2020.08.057 -
Journal of Pharmaceutical Sciences Feb 1995Heparin is a polydisperse, heterogeneous polysaccharide that has been used as an anticoagulant for the past 50 years. The molecular weight determination of this...
Heparin is a polydisperse, heterogeneous polysaccharide that has been used as an anticoagulant for the past 50 years. The molecular weight determination of this important drug has traditionally relied on gel permeation chromatography, which requires the use of well-defined molecular weight standards that are not easily obtained. We have investigated the use of 13C-NMR spectroscopy for measuring the number average molecular weight of heparin. The signal intensities of the reducing end and internal anomeric carbons, having distinctive chemical shifts in the 13C-NMR spectrum, were used to determine the molecular weight. Distortionless enhancement polarization transfer was found to provide a better quantitation of signal intensities of anomeric carbons than broad band decoupling or selective decoupling of anomeric protons. Signal averaging over 300,000 transients, requiring approximately 48 h on a 360 MHz NMR spectrometer, resulted in the measurement of the number average molecular weight (approximately 10,000 Da) of heparin. 13C-NMR spectroscopy does not require the use of difficult to obtain molecular weight standards and thus is particularly well-suited for workers in the pharmaceutical industry.
Topics: Animals; Heparin, Low-Molecular-Weight; Magnetic Resonance Spectroscopy; Molecular Weight; Swine
PubMed: 7738804
DOI: 10.1002/jps.2600840218 -
Journal of Cellular and Comparative... Feb 1955
Topics: Enzymes; Luciferases; Molecular Weight
PubMed: 14367435
DOI: 10.1002/jcp.1030450103 -
Science (New York, N.Y.) Sep 1964Sedimentation and immunodiffusion experiments indicate that the molecular weight for the minimum molecular unit of C-phycocyanin is 30,000. This result agrees with an...
Sedimentation and immunodiffusion experiments indicate that the molecular weight for the minimum molecular unit of C-phycocyanin is 30,000. This result agrees with an analysis of available data on amino acid content for C-phycocyanins from several different algae.
Topics: Amino Acids; Chemistry Techniques, Analytical; Eukaryota; Molecular Weight; Phycocyanin; Proteins; Research
PubMed: 14172617
DOI: 10.1126/science.145.3636.1054 -
Carbohydrate Polymers Mar 2017The physicochemical properties and biological functions of hyaluronan (HA) are closely related to its molecular weight (MW) and molecular weight distribution (MWD)....
The physicochemical properties and biological functions of hyaluronan (HA) are closely related to its molecular weight (MW) and molecular weight distribution (MWD). Therefore, it is crucially important to provide a reliable characterization of these parameters for proper use of HA and its degradation products in both chemical and clinical fields. In this study, we present a novel method for the preparation of HA fragments of defined size with narrow molecular weight distribution. The HA fractionation was performed using an anion-exchange chromatography and is applicable either after enzymatic or chemical hydrolysis of polymeric HA. Isolated fractions with a molecular weight ranging from 3000-420,000gmol were analyzed by size exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). Hundred-milligram scale HA fragments were obtained from 5g hyaluronan starting material. Independently on weight-average molecular weight (M), the polydispersity index (PDI) of the HA fractions was less than 1.23. The fractionation methodology can be easily up-scaled and is applicable on any negatively charged polymers. We have also found that PDI is insufficient to characterize almost monodisperse fractions and for proper material characterization we proposed a new characteristic termed "distribution angle", calculated from the slope of the cumulative molecular weight distribution curve. Compared to PDI, the distribution angle reflects more efficiently changes in size distribution and thus is highly recommended to be used along with M determination of any polymer.
Topics: Chromatography, Gel; Hyaluronic Acid; Hydrolysis; Molecular Weight; Polymers
PubMed: 28115087
DOI: 10.1016/j.carbpol.2016.12.045 -
Journal of the American Chemical Society Nov 1965
Topics: Molecular Weight; RNA, Transfer; Saccharomyces
PubMed: 5844470
DOI: 10.1021/ja00949a055