scholarly journals Chemical and enzymatic destruction of chondroitin sulfate from Arctic skate

Vestnik MGTU ◽  
2021 ◽  
Vol 24 (3) ◽  
pp. 267-276
Author(s):  
Y. A. Kuchina ◽  
I. N. Konovalova ◽  
V. Y. Novikov ◽  
N. V. Dolgopyatova ◽  
V. Ya. Kuznetsov
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Chondroitin Sulfate ◽  
High Performance ◽  
Pharmaceutical Preparation ◽  
Average Molecular Weight ◽  
The Arctic ◽  
Cartilage Tissue ◽  
Crystallinity Degree ◽  
Chemical Destruction

Due to its biocompatibility with human and animal tissues, low toxicity, and biodegradability, chondroitin sulfate (CS) is of great interest for medicine. Since CS is used as a pharmaceutical preparation, its molecular weight and solubility determine the possibilities of its use. This work presents the results of studying the chemical and enzymatic destruction of CS macromolecules and its effect on the molecular weight, solubility and crystallinity degree of the polysaccharide. CS was obtained from the cartilaginous tissue of the Arctic skate ( Amblyraja hyperborea ). At the stage of cartilage tissue fermentolysis, the enzymes pancreatin, hepatopancreatin and protosubtil were used. The obtained CS samples were identified by IR spectroscopy. Enzymatic destruction of glycosidic bonds in cholesterol macromolecules was carried out with a 1 % solution of the enzyme hepatopancreatin, chemical destruction with hydrogen peroxide and hydrochloric acid. The CS content in the samples was determined by the Dische method. The chemical composition of CS samples was evaluated by standard methods. The average molecular weight (MW) was determined using high performance liquid chromatography and the nephelometric method. The crystallinity degree (CD) was determined by graphical processing of diffraction patterns obtained by X-ray phase analysis of CS samples. It was found that under the action of hepatopancreatin and hydrogen peroxide, deep destruction of chondroitin sulfate occurs, to the formation of low molecular weight and oligomeric fragments. Under conditions of acid destruction in 0.5 N HCl for 20 min the MW of chondroitin sulfate is reduced by 10 % compared to the initial one. Acid destruction causes a significant decrease in the CD of the CS samples. For CS samples not degraded in acid, the solubility in distilled water increases with decreasing MW and CD. The solubility of CS after acid destruction in the range of pH = 5-9 units is 99.0 ± 0.5 %. This high solubility is most likely explained by the significant content of the amorphous phase in the samples.

scholarly journals Identification of particulate organosulfates in three megacities at the middle and lower reaches of the Yangtze River

2015 ◽  
Vol 15 (15) ◽  
pp. 21415-21448 ◽  
Author(s):  
X. K. Wang ◽  
S. Rossignol ◽  
Y. Ma ◽  
L. Yao ◽  
M. Y. Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Yangtze River ◽  
High Performance ◽  
Average Molecular Weight ◽  
Photochemical Reactions ◽  
Degree Of Saturation ◽  
The Yangtze River ◽  
Seasonal And Diurnal Variations ◽  
Degree Of Oxidation ◽  
Kendrick Mass Defect

Abstract. PM2.5 filter samples have been collected in three megacities i.e., Wuhan (WH), Nanjing (NJ), and Shanghai (SH) at the middle and lower reaches of the Yangtze River, respectively. Analysis of those samples using an ultra-high performance liquid chromatography (UHPLC) coupled to an orbitrap mass spectrometer (MS) allowed detection of about two hundred particulate organosulfates (OSs), including dozens of nitrooxy-organosulfates, at each location. While aliphatic OSs represented more than 78 % of the detected OSs at the three locations, aromatic OSs were much less abundant. OSs with two to four isomers accounted for about 50 % of the total OSs on average in these megacities, and the percentage of OSs with six and more isomers in WH was more significant than those in SH and NJ. The average molecular weight, and the degrees of oxidation and saturation of OSs in the WH summer samples were greater than those in WH winter samples. In SH, the average molecular weight and the degree of oxidation of OSs in summer samples were greater than those in winter samples, but the degree of saturation was similar between the two seasons. In summer, the average molecular weight, and the degrees of oxidation and unsaturation of OSs were smallest in WH among the three cities. Between NJ and SH, the average molecular weight and the degree of saturation of OSs were close and the degree of oxidation of OSs in NJ was smaller. Kendrick mass defect diagrams and Van Krevelen diagrams indicated that the characteristics of identified OSs between in NJ and in SH shared better similarity. In addition, the identity and abundance of OSs in SH showed clear seasonal and diurnal variations. OSs in summer were more abundant than they were in winter due to stronger photochemical reactions in summer. The relative abundance of OSs at night was greater than that in the daytime and more nitrooxy-OSs existed at night, probably because of active NO3 radical chemistry at night. In SH summer samples, OSs with 5 and 10 carbons (C5 and C10) were the most abundant, indicating the importance of isoprene and monoterpenes as precursors of OSs, whereas the relative abundances of OSs with 8, 9, and more than 14 carbons (C8, C9, and C14+) were also high in SH winter samples, urging the need to further understand the precursors of OSs.

High Performance Size Exclusion Chromatograph with Computerized Data Reduction for Analysis of Polyethylene and Oligomers

1981 ◽  
Vol 64 (4) ◽  
pp. 999-1007
Author(s):  
Roger C Snyder ◽  
Charles V Breder
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Average Molecular Weight ◽  
Porous Silica ◽  
Size Exclusion ◽  
Dead Volume ◽  
Shape Distortion ◽  
Molecular Weight Range ◽  
Liquid Chromatograph ◽  
Exclusion Chromatography

Abstract A liquid chromatograph is described for the size exclusion chromatography (SEC) of polyethylene and oligomers. The rigid column packing material was 10 µm diameter porous silica. An infrared spectrophotometer was used as the detector. The chromatograph was designed and operated to minimize the degree of chromatographic peak shape distortion resulting from factors such as system dead volume, detector cell design, sample injection volume, and sample concentration. To compensate for peak spreading and skewing, the chromatographic data were analyzed with an IBM 370/168 computer using an APL program. The molecular weight range covered by this SEC system was 100-500 000. Precision and accuracy of Jhe calculated weight average molecular weight (Mw) values for polyethylene standards over this range were ±3 and s±4%, respectively.

Differential Digestion of Different LMWHs by Heparinase-I and Heparinase-II: Drug Developmental Implications.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4084-4084
Author(s):  
Jyothi Maddineni ◽  
Walter P. Jeske ◽  
Omer Iqbal ◽  
Debra A. Hoppensteadt ◽  
Jawed Fareed
Keyword(s):  
Molecular Weight ◽  
Enzymatic Activity ◽  
High Performance ◽  
Uronic Acid ◽  
Specific Binding ◽  
Average Molecular Weight ◽  
Uv Detection ◽  
Molecular Profile ◽  
Heparinase I ◽  
Differential Digestion

Abstract The purpose of this study was to determine the differential digestion of two different batches of branded enoxaparin (Aventis, USA), three generic versions of enoxaparin (GlandPharma, India; Lazar, Argentina; and Biochemie, Brazil), dalteparin (Pfizer, USA) and tinzaparin (Leo, USA) by heparinase-I and heparinase-II. Heparinase-I (Ibex Tech., Montreal, Canada) and heparinase-II (Ram Sasisekharan, MIT, Cambridge, MA) were isolated from Flavobacterium heparinum. The substrate specificity of these enzymes has been inferred from the reducing and non-reducing terminal structures of the di and oligosaccharides formed by digesting heparin. Heparinase-I cleaves the glucosaminidic linkage in GlcN (N-sulfate) a 1–4 IdceA (2-sulfate) and endures C-6 sulfation of hexosamine unit. More susceptibility of polymers such as heparin than oligomers to this enzymatic depolymerization indicates the size dependency of this enzymatic activity. Heparinase-II cleaves all the glucosaminidic linkages in heparin independent of O-and/or N-sulfation as well as the type of uronic acid residue. The non-sulfated substrates are somewhat resistant to this enzyme. The glucosaminidic linkage adjacent to a 3-O-sulfated GlcN residue and the innermost glucosaminidic linkage right next to the glycosaminoglycan-protein linkage region of proteoglycan are resistant to this enzymatic activity (Sugahara et al., 1994, Glycobiology 4, 535–544). In this study, several low molecular weight heparins (LMWHs) produced from different depolymerization methods of unfractionated heparin were digested with heparinase-I and heparinase-II to determine the differential digestion of these two enzymes. Eight different LMWHs with average molecular weight (MW) ranging from 3425 to 6281 Da (in UV detection at 205nm) were prepared at a concentration of 10mg/ml in 0.3M Na2SO4. Each LMWH was incubated with these enzymes (1.0 U/mL) separately for 30 minutes at 37° C in the presence of calcium Following the incubation, the samples were heated at 100° C to inactivate enzymatic activity. The molecular weight profiling of these samples was determined by using a gel permeation chromatography-high performance liquid chromatography (GPC-HPLC) system with UV detection at 205nm. A narrow range calibration method comprised of oligosaccharides and polysaccharides was used to determine the relative molecular profile of the native and digested products. The LMWHs were digested to LMW oligosaccharides with average MW of 1510± 275 Da with heparinase-I and 3071± 1044 Da with heparinase-II. The extent of digestion observed with all the LMWHs was more with heparinase-I than heparinase-II. This may be due to the different specific binding sites available for these enzymes and the requirement of sulfation at different positions in GlcN/uronic acid residues. All the LMWHs were equally digested into oligosaccharides (di, tetra and hexa) with heparinase-I. However heparinase-II resulted in the formation of only hexa, octa and decasaccharides. These results show that the LMWHs were more susceptible to heparinase-I than heparinase-II. The possible reason for the less susceptibility of these compounds to heparinase-II is likely due to the oligosaccharide composition and degree and pattern of sulfation in GlcN/uronic acid residues of these compounds. The heparinase-I and heparinase-II digestion can therefore be used in the profiling of these agents.

Exploring the formaldehyde reactivity of tannins with different molecular weight distributions: bayberry tannins and larch tannins

Holzforschung ◽  
2020 ◽  
Vol 74 (7) ◽  
pp. 673-682 ◽  
Author(s):  
Tao Yang ◽  
Mengqi Dong ◽  
Juqing Cui ◽  
Lu Gan ◽  
Shuguang Han
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Average Molecular Weight ◽  
Degree Of Polymerization ◽  
Standard Curve ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Curve Method ◽  
Standard Curve Method ◽  
Tannin Degradation

AbstractIn recent years, tannin degradation has been used to obtain tannin materials with an optimal molecular weight distribution (MWD) for synthesizing tannin-formaldehyde (TF) resin with high performance, but the optimal MWD of tannins is still unknown. The excellent formaldehyde reactivity of tannins is the basis for the synthesis of high-performance TF resin. Based on the formaldehyde reactivity of tannins, bayberry tannins and larch tannins were used to explore the optimal MWD of tannins for TF resin synthesis. Progressive solvent precipitation (PSP) was used to obtain tannin fractions with different MWDs. The formaldehyde reactivity of tannins was determined using the modified Stiansy method combined with the standard curve method (GB/T 17657-2013). The bayberry tannin fraction [weight-average molecular weight (Mw) of acetylated tannin: 4115, mean degree of polymerization (mDP): 6.64] and the larch tannin fraction (Mw of acetylated tannin: 3906, mDP: 5.84) had the best formaldehyde reactivity. Furthermore, significant differences in the formaldehyde reactivity of condensed tannins (CTs) with different MWDs were observed. The obtained results can be used to purposefully degrade tannins to achieve an optimal MWD, which is beneficial for the production of TF adhesives with high performance.

Isolation and Characteristic of Chondroitin Sulfate from Grass Carp Scales

2011 ◽  
Vol 391-392 ◽  
pp. 1003-1007
Author(s):  
Shuang Li Xiong ◽  
An Lin Li ◽  
Min Juan Shi
Keyword(s):  
Molecular Weight ◽  
Chemical Analysis ◽  
Chondroitin Sulfate ◽  
Grass Carp ◽  
Average Molecular Weight ◽  
Sulfate Group ◽  
Weight Average Molecular Weight ◽  
Element Analysis ◽  
Crude Polysaccharide ◽  
Fast Flow

Papain and alcalase were successively used to hydrolyze grass carp scales for preparation of crude polysaccharide. Chondroitin sulfate were further purified by DEAE-Sepharose Fast Flow and Sepharose 6 Fast Flow gel column chromatograph, and indentified by IR, NMR, element analysis and chemical analysis. Three polysaccharide fractions including chondroitin sulfate were fistly obtained from grass carp scales. The weight-average molecular weight of chondroitin sulfate was 46168 Da. The contents of various elements (C, H, N, S, O) in chondroitin sulfate were 28.89 %, 3.80 %, 3.36 %, 6.71 % and 47.16 %, respectively. The results of IR, NMR and chemical analysis exhibited that the sulfate group in chondroitin sulfate be O-linked in position 4 of N-acetyl-D-galactosamine.

Monitoring of Lignin and Hemicelluloses in Spent Cooking Liquor during Kraft Delignification

Holzforschung ◽  
2000 ◽  
Vol 54 (1) ◽  
pp. 66-70 ◽  
Author(s):  
T. Bikova ◽  
V. Klevinska ◽  
A. Treimanis
Keyword(s):  
Molecular Weight ◽  
Rapid Method ◽  
High Performance ◽  
Average Molecular Weight ◽  
Size Exclusion ◽  
Black Alder ◽  
Exclusion Chromatography ◽  
Glass Column ◽  
Kraft Cooking ◽  
Cooking Liquor

Summary A direct and rapid method for determining the average molecular weight (MW) and content of lignin and hemicelluloses in spent cooking liquor by high performance size-exclusion chromatography (HPSEC) using a cartridge glass column and 2.5 mM NaOH as an eluent was developed. A Uv290 detector in line with a RI detector was applied to characterise lignin and hemicelluloses, respectively, from liquor during the kraft cooking of grey and black alder wood. During the main delignification stage, the concentration of high-MW wood components in liquor changed through the maximum. The MW values of hemicelluloses in the liquor decreased to DPn = 30 ± 5 and DPw = 55 ± 5. The M̄ n and M̄ w of lignin in spent kraft cooking liquor during the main and final delignification stages did not exceed 3000 and 5000, respectively.

The Catalytic Synthesis of Wholly Aromatic Polyesters Based on 4-hydroxybenzoic Acid via Direct Esterification

2020 ◽  
Vol 869 ◽  
pp. 112-118
Author(s):  
Timur R. Deberdeev ◽  
Alsu I. Akhmetshina ◽  
Liana K. Karimova
Keyword(s):  
Phase Transition ◽  
Molecular Weight ◽  
High Performance ◽  
Crystalline State ◽  
Average Molecular Weight ◽  
Practical Importance ◽  
Catalytic Synthesis ◽  
Hydroxybenzoic Acid ◽  
Direct Esterification ◽  
Aromatic Polyesters

The synthesis and properties of wholly aromatic polyesters are of considerable practical importance to create functional and high-performance materials. In the present study, by means of catalytic polyesterification using titanium (IV) butoxide, we’ve synthesized wholly aromatic oligomers derived from 4-hydroxybenzoic acid (HBA), aromatic diacids and dibasic phenols. As revealed by FTIR measurements, the average molecular weight of oligomers has varied from 500 to 1400. The results of DSC have shown endotherm peaks attributed to a phase transition of low-molecular oligomers from crystalline state to mesophase and further isotropization. The synthesized oligomers were resistant to high temperatures up to about 300-320 °C.

scholarly journals Crystallinity of Electrospun and Centrifugal Spun Polycaprolactone Fibers: A Comparative Study

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Eva Kuzelova Kostakova ◽  
Laszlo Meszaros ◽  
Gabriela Maskova ◽  
Lenka Blazkova ◽  
Tamas Turcsan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Production Technology ◽  
Average Molecular Weight ◽  
Degree Of Crystallinity ◽  
Fibrous Materials ◽  
Scanning Calorimetry ◽  
Crystallinity Degree ◽  
A Minor ◽  
Technology Effects ◽  
The Degree Of Crystallinity

Crystalline properties of semicrystalline polymers are very important parameters that can influence the application area. The internal structure, like the mentioned crystalline properties, of polymers can be influenced by the production technology itself and by changing technology parameters. The present work is devoted to testing of electrospun and centrifugal spun fibrous and nanofibrous materials and compare them to foils and granules made from the same raw polymer. The test setup reveals the structural differences caused by the production technology. Effects of average molecular weight are also exhibited. The applied biodegradable and biocompatible polymer is polycaprolactone (PCL) as it is a widespread material for medical purposes. The crystallinity of PCL has significant effect on rate of degradation that is an important parameter for a biodegradable material and determines the applicability. The results of differential scanning calorimetry (DSC) showed that, at the degree of crystallinity, there is a minor difference between the electrospun and centrifugal spun fibrous materials. However, the significant influence of polymer molecular weight was exhibited. The morphology of the fibrous materials, represented by fiber diameter, also did not demonstrate any connection to final measured crystallinity degree of the tested materials.

scholarly journals DTA and DSC study on the effect of mechanical dispersion on poly(tetrafluorethylene) properties

2014 ◽  
Vol 22 (2) ◽  
pp. 63-74
Author(s):  
Mihai Dumitraşa
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Crystallization Behaviour ◽  
Mechanical Degradation ◽  
Mechanical Processing ◽  
Crystallinity Degree ◽  
Mechanical Wear ◽  
Mechanical Dispersion ◽  
Polymer Properties ◽  
Melting And Crystallization

Abstract Poly(tetrafluorethylene) particles were obtained by mechanical processing of the formed polymer (Teflon bar). In order to assess the effect of mechanical wear on polymer properties, their melting and crystallization behaviour was investigated by DSC and DTA, and the results were compared to the ones obtained for the native polymer. An increase of the crystallinity degree and an accentuated decrease of the average molecular weight were found for the samples submitted to mechanical wear, as a result of mechanical degradation of the polymer

scholarly journals Valorization of Lignin via Oxidative Depolymerization with Hydrogen Peroxide: Towards Carboxyl-Rich Oligomeric Lignin Fragments

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2717
Author(s):  
Ulrike Junghans ◽  
Justin J. Bernhardt ◽  
Ronja Wollnik ◽  
Dominik Triebert ◽  
Gerd Unkelbach ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Average Molecular Weight ◽  
Scale Up ◽  
Water Mixture ◽  
Pulp Bleaching ◽  
Solvent Fractionation ◽  
Whole Process ◽  
Acetone Water ◽  
Lignin Depolymerization

The extraction and characterization of defined and carboxyl-rich oligomeric lignin fragments with narrow molecular weight distribution is presented herein. With regard to the well-known pulp bleaching process, oxidative lignin depolymerization was investigated using hydrogen peroxide in an aqueous alkaline solution (i.e., at T = 318 K, t = 1 h) and subsequent selective fractionation with a 10/90 (v/v) acetone/water mixture. While the weight average molecular weight (MW) of lignin in comparison to the starting material was reduced by 82% after oxidation (T = 318 K, t = 1 h, clignin = 40 g L−1, cH2O2 = 80 g L−1, cNaOH = 2 mol L−1) and subsequent solvent fractionation (T = 298 K, t = 18 h, ccleavage product = 20 g L−1), the carboxyl group (–COOH) content increased from 1.29 mmol g−1 up to 2.66 mmol g−1. Finally, the successful scale-up of this whole process to 3 L scale led to gram amounts (14% yield) of oligomeric lignin fragments with a MW of 1607 g mol−1, a number average molecular weight (MN) of 646 g mol−1, a narrow polydispersity index of 3.0, and a high –COOH content of 2.96 mmol g−1. Application of these oligomeric lignin fragments in epoxy resins or as adsorbents is conceivable without further functionalization.

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