scholarly journals The mode of action of 4-methylumbelliferyl β-d-xyloside on the synthesis of chondroitin sulphate in embryonic-chicken sternum

1977 ◽  
Vol 168 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Kenneth D. Gibson ◽  
Barbara J. Segen
Keyword(s):  
Molecular Weight ◽  
Chondroitin Sulphate ◽  
Average Molecular Weight ◽  
Gel Filtration ◽  
Proteoglycan Synthesis ◽  
Serum Factors ◽  
Elution Pattern ◽  
Embryonic Chicken ◽  
Kinetics Of ◽  
Stimulation Of

1. Embryonic-chicken sterna, incubated in medium containing 0.1mm-4-methylumbelliferyl β-d-xyloside (4-methylcoumarin 7-β-d-xyloside), synthesize proteochondroitin sulphate that is significantly undersulphated and shorter than usual [Gibson, Segen & Audhya (1977) Biochem. J.162, 217–233]. 2. Neither the β-d-galactoside nor the β-d-glucuronide of 4-methylumbelliferone, nor 4-methylumbelliferone itself, produced the effects. The only metabolites of 4-methylumbelliferone that were detected in cartilages exposed to 4-methylumbelliferyl β-d-xyloside were unchanged xyloside and chondroitin sulphate covalently attached to 4-methylumbelliferone. 3. Gel filtration of salt extracts of sterna incubated in medium containing the xyloside showed that there were two pools of chondroitin sulphate in the tissue. One pool was identified, on the basis of its elution pattern and the linear kinetics of incorporation of sulphate into it, as proteochondroitin sulphate. Incorporation into the other pool, whose properties suggested that it was methylumbelliferyl-chondroitin sulphate, indicated that it underwent partial turnover. The molecular weight of this chondroitin sulphate was about 19000, and it appeared to be about 70% sulphated. 4. When sterna were incubated in medium containing the xyloside, there was a very large incorporation of sulphate and glucose into glycosaminoglycans that were released into the incubation medium. This contrasts with incubations of sterna in the absence of the xyloside, in which less than 5% of the sulphate incorporated could be recovered from the medium. The glycosaminoglycan released into the medium was 4-methylumbelliferyl-chondroitin sulphate, whose average molecular weight was 7000–8000 and degree of sulphation more than 95%. 5. Incorporation of sulphate into proteochondroitin sulphate was stimulated more than 3-fold by addition of 20% (v/v) human serum and 10nm-l-3,3′,5-tri-iodothyronine. Incorporation into methylumbelliferyl-chondroitin sulphate, in either the tissue or the medium, was not significantly altered. 6. The decrease in chain length and degree of sulphation of proteochondroitin sulphate is explained in terms of competition between peptide-linked primers and methylumbelliferone-containing primers at the intracellular sites of polysaccharidechain elongation and sulphation. The implications of the results for the mechanism of stimulation of proteoglycan synthesis by serum factors are discussed.

scholarly journals The effect of β-d-xylosides on chondroitin sulphate biosynthesis in embryonic chicken cartilage in the absence of protein synthesis inhibitors

1977 ◽  
Vol 162 (2) ◽  
pp. 217-233 ◽  
Author(s):  
K D Gibson ◽  
B J Segen ◽  
T K Audhya
Keyword(s):  
Protein Synthesis ◽  
Incubation Medium ◽  
Chondroitin Sulphate ◽  
Gel Filtration ◽  
Protein Synthesis Inhibitors ◽  
Serum Factors ◽  
Embryonic Chicken ◽  
Low Concentrations ◽  
Normal Human

Incorporation of [35S]]sulphate, [3H]glucose and [3H]serine into glycosaminoglycans and proteoglycans of embryonic-chicken sternum was measured in vitro in incubation medium containing 4-methylumbelliferyl beta-D-xyloside or p-nitrophenyl beta-D-xyloside at low concentrations, and in the absence of inhibitors of protein synthesis. Incorporation of sulphate was decreased by 80% in incubations in which 1mM-4-methylumbelliferyl beta-xyloside or 2.5 mM-p-nitrophenyl beta-xyloside was present; under these conditions, serum factors stimulated incorporation to only a small extent. When the concentration of the xyloside was decreased tenfold, incorporation of sulphate was inhibited by 60-70%, but when normal human serum or L-3,3′,5-tri-iodothyronine or both were also added to the incubation medium, incorporation was markedly stimulated. Experiments in which [35S]sulphate and [3H]glucose were incorporated simultaneously, and enzymic analysis of glycosaminoglycans formed in such experiments, indicated that chondroitin sulphate formed in the presence of 0.1 mM-4-methylumbelliferyl beta-xyloside contained 30-40% less sulphate than did chondrotin sulphate synthesized in the absence of xylosides. Similar experiments, with [3H]serine instead of [3H]glucose, suggested also a 20-30% decrease in chain length of the chondroitin sulphate; this was confirmed by direct gel filtration of labelled glycosaminoglycans on a calibrated column. Incorporation of [3H]glucose or [3H]serine was stimulated by serum and tri-iodothyronine in parallel with incorporation of sulphate. The changes seen in the total chondroitin sulphate were mirrored in the major proteoglycan fraction, purified by isopycnic centrifugation of salt-extracted proteoglycans. The labelling pattern of chondroitin sulphate from this proteoglycan indicated that decreased sulphation of chondroitin sulphate was largely due to the inferior ability of short polysaccharide chains to accept sulphate, with some direct interference with transfer of sulphate to all chains. The results also suggested that the action of serum factors on synthesis of proteochondroitin sulphate is exercised at the level of either protein synthesis or transport to the sites of initiation of polysaccharide synthesis.

Probing the molecular weights of sweetgum and pine kraft lignin fractions

TAPPI Journal ◽  
2021 ◽  
Vol 20 (6) ◽  
pp. 381-391
Author(s):  
JULIANA M. JARDIM ◽  
PETER W. HART ◽  
LUCIAN LUCIA ◽  
HASAN JAMEEL
Keyword(s):  
Molecular Weight ◽  
Black Liquor ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Systematic Investigation ◽  
Kraft Pulping ◽  
Molecular Weights ◽  
Lignin Recovery ◽  
Lignin Reactivity ◽  
Kinetics Of

The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physicochemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30–150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to deter- mine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weightlignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.

scholarly journals The isocitrate dehydrogenases of Acinetobacter lwoffi. Separation and properties of two nicotinamide–adenine dinucleotide phosphate-linked isoenzymes

1972 ◽  
Vol 130 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Colin H. Self ◽  
P. David J. Weitzman
Keyword(s):  
Molecular Weight ◽  
Ph Dependence ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Molecular Size ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Low Concentrations ◽  
Stimulation Of

Two isoenzymes of NADP-linked isocitrate dehydrogenase have been identified in Acinetobacter lwoffi and have been termed isoenzyme-I and isoenzyme-II. The isoenzymes may be separated by ion-exchange chromatography on DEAE-cellulose, by gel filtration on Sephadex G-200, or by zonal ultracentrifugation in a sucrose gradient. Low concentrations of glyoxylate or pyruvate effect considerable stimulation of the activity of isoenzyme-II. The isoenzymes also differ in pH-dependence of activity, kinetic parameters, stability to heat or urea and molecular size. Whereas isoenzyme-I resembles the NADP-linked isocitrate dehydrogenases from other organisms in having a molecular weight under 100000, isoenzyme-II is a much larger enzyme (molecular weight around 300000) resembling the NAD-linked isocitrate dehydrogenases of higher organisms.

Movements of Phosphorus Between its Biologically Important Forms in Lake Water

1973 ◽  
Vol 30 (10) ◽  
pp. 1525-1536 ◽  
Author(s):  
D. R. S. Lean
Keyword(s):  
Molecular Weight ◽  
Lake Water ◽  
Membrane Filtration ◽  
Organic Phosphorus ◽  
Gel Filtration ◽  
Particulate Fraction ◽  
Low Molecular Weight ◽  
Radioactive Phosphorus ◽  
Dissolved Phosphorus ◽  
Kinetics Of

A model consistent with the kinetics of phosphorus in epilimnetic lake water was developed. Adding 32PO4 to lake water and separating the major forms of dissolved phosphorus by Sephadex gel filtration showed that the exchange mechanism between inorganic phosphate and the particulate fraction predominates. At the same time, a low-molecular-weight phosphorus compound is excreted which combines with colloids in lake water, releasing phosphate from the colloid and making the phosphate available for "transfer" again. This rapid cycling of phosphorus between the four principal forms — the particulate fraction, the low-molecular-weight P compound, colloidal P, and phosphate — appears to contribute to formation of colloids in lake water. No direct complexing of phosphate to the colloid was observed. Only in the presence of algae, bacteria, and other particulate matter did the radioactive phosphorus move to the low-molecular weight and the colloidal forms. The low-molecular-weight compound is negatively charged, as is the colloidal P, but to a lesser degree. Both are removed by anion exchange materials along with phosphate, but the rate that they move into the fraction removed by membrane filtration is different from that for phosphate. When filtrate is refiltered a large amount of the colloidal P is retained by the filter. This complicates measurements of transfer and makes previous studies on utilization of dissolved organic phosphorus of doubtful value since corrections for filter retention were rarely, if ever, made.

SOME OBSERVATIONS ON THE MOLECULAR FORM OF CHONDROITIN SULPHATE

1956 ◽  
Vol 34 (5) ◽  
pp. 993-1005 ◽  
Author(s):  
R. V. Webber ◽  
S. T. Bayley
Keyword(s):  
Molecular Weight ◽  
Molecular Form ◽  
Chondroitin Sulphate ◽  
Average Molecular Weight ◽  
Scattering Data ◽  
Tryptic Digestion ◽  
Viscosity Data ◽  
Number Average Molecular Weight ◽  
Partial Analysis ◽  
Bovine Cartilage

The physical properties of a preparation of chondroitin sulphate extracted from bovine cartilage with calcium chloride have been measured at various stages of purification. After removal of free protein, the extract has a number-average molecular weight, from sedimentation and viscosity data, of about 1.0 × 106. After tryptic digestion, the molecular weight of the extract is 39,000 on a number average basis from sedimentation and viscosity data, and about 145,000 on a weight average basis from light scattering data. At both stages of purification, the extract is widely polydisperse and exhibits streaming birefringence in aqueous but not in salt solution. Before digestion, the particles evidently represent aggregates of polysaccharide molecules linked in an end-to-end arrangement by peptides; tryptic digestion partially destroys these peptide linkages. It does not appear, from a partial analysis of the amino acids present, that the origin of the protein or peptide material is collagen.

scholarly journals Selective suppression of the major idiotypic component of an antihapten response by soluble T cell-derived factors with idiotypic or anti-idiotypic receptors.

1980 ◽  
Vol 151 (5) ◽  
pp. 1213-1231 ◽  
Author(s):  
Y Hirai ◽  
A Nisonoff
Keyword(s):  
Molecular Weight ◽  
T Cells ◽  
T Cell ◽  
Gel Filtration ◽  
Humoral Response ◽  
Spleen Cells ◽  
Suppressor T Cells ◽  
Soluble Factors ◽  
Selective Suppression ◽  
Stimulation Of

Evidence is presented for the selective suppression of the major idiotypic component of the humoral response to the phenylarsonate hapten by soluble factors derived from T cells (TsF). The existence of TsF with anti-idiotypic receptors was also demonstrated. It was found that TsF with idiotypic and anti-idiotypic receptors coexist in cultures of spleen cells prepared from idiotypically suppressed, hyperimmunized mice. By gel filtration the molecular weight of each factor was found to be 50,000-100,000. Each is sensitive to trypsin and is bound to a column containing anti-H-2a antibodies. Evidence is discussed which suggests the possibility of mutual stimulation of suppressor T cells with idiotypic and anti-idiotypic receptors.

Algal Ferredoxin-NADP+ Reductase with Different Molecular-Weight Forms

1979 ◽  
Vol 34 (7-8) ◽  
pp. 637-640 ◽  
Author(s):  
Gerhard Bookjans ◽  
Peter Böger
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Gel Electrophoresis ◽  
Sodium Dodecylsulfate ◽  
Gel Filtration ◽  
Monomeric Form ◽  
Elution Pattern ◽  
Filtration Step ◽  
Different Molecular Weight

Ferredoxin-NADP+ reductase from the microalga Bumilleriopsis was isolated by a combination of affinity chromatography on a flavodoxin-Sepharose 4 B column and usual purification procedures. Both the elution pattern of the final gel filtration step and of the sodium dodecylsulfate (SDS) disc gel electrophoresis indicate that there are at least two different molecular-weight forms of the reductase, a monomeric form and a dimeric one.

Increased growth stimulation of fibroblasts from diabetics by diabetic serum factors of low molecular weight

1980 ◽  
Vol 37 (2) ◽  
pp. 311-317 ◽  
Author(s):  
T. Koschinsky ◽  
C.E. Bünting ◽  
B. Schwippert ◽  
F.A. Gries
Keyword(s):  
Molecular Weight ◽  
Growth Stimulation ◽  
Low Molecular Weight ◽  
Serum Factors ◽  
Stimulation Of

scholarly journals Kinetics of Oxidative Depolymerization of κ-carrageenan by Ozone

2017 ◽  
Vol 12 (2) ◽  
pp. 235 ◽  
Author(s):  
Aji Prasetyaningrum ◽  
Ratnawati Ratnawati ◽  
Bakti Jos
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Second Order ◽  
Kinetics Model ◽  
Ozone Treatment ◽  
Capillary Viscometer ◽  
Number Average Molecular Weight ◽  
Constant Flow Rate ◽  
Kinetics Of ◽  
Weight Data

Depolymerization kinetics of κ-carrageenan by ozone treatment has been studied at various pHs and times. The purified κ-carrageenan with the initial molecular weight of 271 kDa was dispersed in water to form (1 % w/v) solution. Ozone with 80±2 ppm concentration and constant flow rate of 3 L.min-1 was bubbled into the κ-carrageenan solution. The experiments were conducted at pH of 3, 7, and 10 at     different times (5, 10, 15, and 20 minutes) of ozonation. The viscosity of the solution was measured   using Ubbelohde capillary viscometer, which was then used to find the number-average molecular weight by Mark-Houwink equation. The number-average molecular weight data was treated using zero, first, and the second-order reaction kinetics model, to obtain the kinetics of κ-carrageenan depolymerization. The depolymerization is assumed to occur by random scission. The results show that the kinetics rate constant of κ-carrageenan depolymerization is higher at lower pHs. The second-order model is more suitable for describing the kinetics of depolymerization of κ-carrageenan by ozonation process. The rate constants for the second-order kinetics model are 5.45×10-4 min-1, 1.27×10-4 min-1, and 7.21×10-5 min-1 for pH 3, 7, and 10, respectively. The actual values of reaction order under acid and    alkali conditions are ranging from 1.88 to 1.90. Copyright © 2017 BCREC Group. All rights reserved.Received: 21st November 2016; Revised: 27th January 2017; Accepted: 18th February 2017How to Cite: Prasetyaningrum, A., Ratnawati, R., Jos, B. (2017). Kinetics of Oxidative Depolymerization of κ-carrageenan by Ozone. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2): 235-242 (doi:10.9767/bcrec.12.2.805.235-242)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.805.235-242

scholarly journals Kinetics and Thermodynamics of Ultrasound-Assisted Depolymerization of κ-Carrageenan

2016 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Ratnawati Ratnawati ◽  
Aji Prasetyaningrum ◽  
Dyah Hesti Wardhani
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Chain Scission ◽  
Number Average Molecular Weight ◽  
Covalent Bonds ◽  
Exponential Factor ◽  
Kinetics And Thermodynamics ◽  
Thermal Depolymerization ◽  
Ultrasound Assisted ◽  
Kinetics Of

<p>The ultrasound-assisted depolymerization of κ-carrageenan has been studied at various temperatures and times. The κ-carrageenan with initial molecular weight of 545 kDa was dispersed in water to form a 5 g/L solution, which was then depolymerized in an ultrasound device at various temperatures and times. The viscosity of the solution was measured using Brookfield viscometer, which was then used to find the number-average molecular weight by Mark-Houwink equation. To obtain the kinetics of κ-carrageenan depolymerization, the number-average molecular weight data was treated using midpoint-chain scission kinetics model. The pre-exponential factor and activation energies for the reaction are 2.683×10<sup>-7</sup> mol g<sup>-1</sup> min<sup>-1</sup> and 6.43 kJ mol<sup>-1</sup>, respectively. The limiting molecular weight varies from 160 kDa to 240 kDa, and it is linearly correlated to temperature. The results are compared to the result of thermal depolymerization by calculating the half life. It is revealed that ultrasound assisted depolymerization of κ-carrageenan is faster than thermal depolymerization at temperatures below 72.2°C. Compared to thermal depolymerization, the ultrasound-assisted process has lower values of E<sub>a</sub>, ΔG<sup>‡</sup>, ΔH<sup>‡</sup>, and ΔS<sup>‡</sup>, which can be attributed to the ultrasonically induced breakage of non-covalent bonds in κ-carrageenan molecules. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 10<sup>th</sup> November 2015; Revised: 18<sup>th</sup> January 2016; Accepted: 19<sup>th</sup> January 2016</em></p><p><strong>How to Cite</strong>: Ratnawati, R., Prasetyaningrum, A., Wardhani, D.H. (2016). Kinetics and Thermodynamics of Ultrasound-Assisted Depolymerization of κ-Carrageenan. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11(1): 48-58. (doi:10.9767/bcrec.11.1.415.48-58)</p><p><strong>Permalink/DOI</strong>:<a href="/index.php/bcrec/editor/viewMetadata/%20http:/dx.doi.org/10.9767/bcrec.11.1.415.48-58"> http://dx.doi.org/10.9767/bcrec.11.1.415.48-58</a></p><p> </p>

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