Purification and some properties of five endo-1,4-β-D-xylanases and β-D-xylosidase produced by a strain of Aspergillus niger

1979 ◽  
Vol 57 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Michael John ◽  
Bernd Schmidt ◽  
Jurgen Schmidt
Keyword(s):  
Molecular Weight ◽  
Aspergillus Niger ◽  
Substrate Specificity ◽  
Culture Medium ◽  
The Other ◽  
Crystalline Cellulose ◽  
Gel Chromatography ◽  
Molecular Weights ◽  
Optimal Activity ◽  
Equatorial Forest

Five different xylanases and a β-D-xylosidase in the culture medium of Aspergillus niger have been purified to homogeneity from 13- to 52-fold by a procedure of gel and hydroxylapatite chromatography. The strain was isolated from soil of the African equatorial forest. Gel chromatography of the purified enzymes indicated that three of the xylanases have molecular weights of 31 000 and the other two xylanases have molecular weights of 50 000.β-D-Xylosidase has a molecular weight of 78 000. The pH curves of the xylanases were quite diverse and showed pH optima ranging from 4.0 to 6.5. Characteristic action patterns were obtained for each of the purified xylanases by gel chromatography of the xylan digests on Bio-Gel P-2. The enzymes degraded arabinoxylan by an endomechanism, producing L-arabinose, D-xylose, xylobiose, and a mixture of branched arabinose–xylose and D-xylose oligosaccharides. All xylanases seemed to be capable of liberating L-arabinose from either arabinoxylan or the arabinose–xylose oligosaccharides. Branched arabinose-containing D-xylose oligosaccharides were slowly hydrolyzed, so that these sugars accumulate in the digest. Two xylanases showed relatively broad substrate specificity and were able to degrade also crystalline cellulose. β-D-Xylosidase showed optimal activity at pH 6.7 to 7.0 and at 42 °C. The Km for o-nitrophenyl-β-D-xylopyranoside was 0.22 mM and xylotriose was hydrolyzed more rapidly than xylobiose.

Subunit components of casein micelles from bovine, ovine, caprine and equine milks

1989 ◽  
Vol 56 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Tomotada Ono ◽  
Hideaki Kohno ◽  
Satoshi Odagiri ◽  
Toshio Takagi
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
High Performance ◽  
Laser Light ◽  
Laser Light Scattering ◽  
The Other ◽  
Gel Chromatography ◽  
Casein Micelles ◽  
Molecular Weights ◽  
Combined Use

SummarySubunit components of ovine, caprine and equine casein micelles were separated by gel chromatography using a TSK-G4000SW high-performance column and the subunit components of the fractions analysed and compared with bovine casein. Molecular weights of the casein complexes were determined by the combined use of high-performance gel chromatography and low-angle laser light scattering. The caprine and ovine caseins were separated into three peaks (F2, F3 and F4) which were similar to those of bovine casein with respect to composition and molecular weight (500, 100 and 23 K). These F2, F3 and F4 peaks consisted mainly of αs- and κ-casein, αs- and β-casein and β-casein respectively. The equine casein was separated into two components corresponding to F3 and F4 of bovine casein. These F3 and F4 peaks consisted mainly of αs- and β-casein and β-casein respectively. The molecular weight of equine F3 (850 K) was different from that of the other three species. The contents of F2 and F4 in these caseins were dependent on the contents of κ-casein and β-casein respectively.

Studies on Soluble Fibrin Complexes as a Function of pH

1975 ◽  
Author(s):  
Y. Benabid ◽  
E. Concord ◽  
M. Suscillon
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Gel Electrophoresis ◽  
Gel Chromatography ◽  
Agarose Gel ◽  
Monomer Mixture ◽  
Soluble Fibrin ◽  
Molecular Weights ◽  
Fibrin Monomer

Purified fibrinogen solutions, incubated with thrombin. CNBr. Sepharose, were subjected to agarose gel chromatography and eluted at different pH (6.5; 7.5; 8.5). Among high molecular weight derivatives formed by thrombin, the major component was a dimer. Gel chromatography at pH 8.5 showed a complexes peak distinct of that from fibrinogen, whereas at pH 6.5, only the fibrinogen peak appeared: fibrin monomer was eluted with fibrinogen as demonstrated by polyacrylamid gel electrophoresis 3.75% pH 8.9. SDS urea electrophoresis after reduction indicated that complexes peak contained two α-chains (α and α′). When fibrinogen was incubated with thrombin in the presence of FSF and calcium, several derivatives with higher and higher molecular weights were formed besides the dimer, and elution profiles of chromatography were identical at pH 6.5 and 8.5, thus indicating stable complexes formation. If fibrinogen-fibrin monomer mixture was subjected to FSF action at different pH, no complexes were formed at pH 6.5. These results confirm that at pH 6.5, any association was prevented.

Effect of Polyvinyl Pyrrolidone Molecular Weight on the Silver Morphology Synthesized by N, N-Dimethylformamide Reduction

2012 ◽  
Vol 509 ◽  
pp. 245-252 ◽  
Author(s):  
Xuan Min Zhu ◽  
Xiu Jian Zhao ◽  
Zhi Yong Ning ◽  
Xiao Tao Sui
Keyword(s):  
Molecular Weight ◽  
Growth Rate ◽  
Silver Nanoparticles ◽  
Growth Process ◽  
Selective Adsorption ◽  
The Other ◽  
Polyvinyl Pyrrolidone ◽  
Final Solution ◽  
High Concentration ◽  
Molecular Weights

Nanosized silver (Ag) was synthesized by reducing high concentration AgNO3 in N, N-dimethylformamide (DMF), in the presence of stabilizer polyvinyl pyrrolidone (PVP). PVP of two different molecular weights (MW=40000, 1300000) at the reaction temperature of 80°C and 100°C were tested for the effect on the formation of diverse silver nanoparticles. Our results indicated that the PVP with different molecular weights plays different role in the controlling of the Ag nanostructure owing to the PVP molecular selective adsorption on different crystal facets, thus affecting the growth rate of different facets of Ag nanoparticles. When all the other conditions kept the same and the temperature of 100°C, if PVP (Mw=40,000) was used, only a small amount of Ag decahedra were found. However, when the PVP with larger molecular weight such as PVP K88 (Mw=1300, 000), a large quantity of the triangular nanoprisms existed in the final solution in spite of the minority of quasi-sphere. The growth process and causation of different silver morphology with two distinct PVP have been briefly discussed.

The thermal degradation of polyvinyl compounds IV. The thermal degradation of the methyl methacrylate copolymers with glycol dimethacrylate and acrylonitrile

1949 ◽  
Vol 199 (1056) ◽  
pp. 39-55 ◽  
Keyword(s):  
Molecular Weight ◽  
Thermal Degradation ◽  
Methyl Methacrylate ◽  
The Other ◽  
Glycol Dimethacrylate ◽  
Acrylonitrile Copolymer ◽  
Molecular Weights ◽  
Quantitative Calculation ◽  
Methacrylate Copolymers ◽  
Cross Links

The effect upon degradation of cross-links, formed by copolymerizing small amounts of glycol dimethacrylate with the methyl methacrylate, and small amounts of acrylonitrile units in the chains has been investigated. Cross-links make no difference to the degradation characteristics according to rate measurements. Molecular weights could not be measured in this case owing to the insolubility of the polymer. The methyl methacrylate-acrylonitrile copolymer degrades in quite a different way from polymer composed of homogeneous methyl methacrylate chains. In this case the chain ruptures initially at or near the acrylonitrile units, the molecular weight falling very rapidly in the initial stages of the reaction. One side of the break is terminated by an acrylonitrile unit which cannot degrade but the other side may sooner or later degrade to the next acrylonitrile unit along the chain. The induction period observed is probably due to the time taken to build up an appreciable concentration of such degradable ends. A quantitative calculation agrees well with this theory.

Separation of Sub-Units of Antihemophilic Factor (AHF) by Agarose Gel Chromatography

1972 ◽  
Vol 27 (02) ◽  
pp. 212-219 ◽  
Author(s):  
H. J Weiss ◽  
Louise L. Phillips ◽  
W. Rosner
Keyword(s):  
Molecular Weight ◽  
Molecular Size ◽  
Void Volume ◽  
Gel Chromatography ◽  
Agarose Gel ◽  
Major Peak ◽  
Molecular Weights ◽  
Congenital Afibrinogenemia ◽  
Weight Substance ◽  
Antihemophilic Factor

SummaryThe molecular weight of antihemophilic factor (AHF) in plasma and cryoprecipitate was studied by chromatography on agarose gel (Bio-Gel A, 1.5 M). At a pH of 7.4 and the ionic strength of plasma, AHF appeared in the void volume as a sharp, symmetrical peak, indicating a molecular weight of 1.5 million or greater. Similar findings were obtained in a patient with congenital afibrinogenemia. At a pH of 7.7, the major peak of AHF-activity was again found in the void volume, but a spreading of activity into higher elution volumes was also observed. In 1 M NaCl, pH 7.4, AHF dissociated into active sub-units of varying molecular size. The molecular weights of the smallest subunits were estimated to be 169,000-194,000. These studies provide further evidence that AHF is a high molecular weight substance, not associated with fibrinogen, whose quarternary structure may be disrupted to produce active sub-units of varying sizes.

Characterization of excretory-secretory antigens of Fasciola hepatica

Parasitology ◽  
1982 ◽  
Vol 85 (1) ◽  
pp. 179-188 ◽  
Author(s):  
D. O. Irving ◽  
M. J. Howell
Keyword(s):  
Molecular Weight ◽  
Culture Medium ◽  
Fasciola Hepatica ◽  
Culture Media ◽  
Minor Component ◽  
Serum Free Medium ◽  
Molecular Weights ◽  
A Minor ◽  
Somatic Antigens

SUMMARYTwenty-one day old Fasciola hepatica were recovered from the livers of infected mice and cultured for 5–7 days in a serum-free medium containing either [C]leucine, [C]isoleucine or [S]methionine, or in a medium containing [C]leucine and serum from a sheep vaccinated with excretory– secretory (ES) antigens of juvenile F. hepatica. All three labelled amino acids were incorporated into fluke proteins. Labelled proteins also appeared in the culture medium. Three major polypeptides detected in the culture media had apparent molecular weights of 26000, 24000 and 23000. All were immunoprecipitated from [C]leucine-labelled culture medium using antisera against fluke somatic antigens raised in rabbits or from sheep vaccinated with ES antigens of juvenile F. hepatica. A polypeptide of molecular weight 27 000 was also prominent in the culture medium when [C]isoleucine was used. This polypeptide was present as a minor component when [C]leucine and [S]methionine were included in the culture media; it did not appear to be immunoprecipitated by the above antisera from [C]leucine-labelled culture medium. In the presence of serum from vaccinated sheep, the ES antigens formed immune complexes which contained the polypeptides mentioned above, together with several higher molecular weight polypeptides. Additionally, a number of minor bands of varying molecular weight were present. After micro-Ouchterlony gel immunodiffusion, 2 precipitin lines formed between the labelled ES antigens and antisera. Electrophoresis of these indicated that the 23000, 24000 and 26000 Dalton labelled polypeptides were present in each. The higher molecular weight and the 27000 Dalton labelled polypeptides were also present in one of the lines.

scholarly journals On the Relationship Between Molecular Mass and Anticoagulant Activity in a Low Molecular Weight Heparin (Enoxaparin)

1992 ◽  
Vol 67 (05) ◽  
pp. 556-562 ◽  
Author(s):  
Ana-Victoria Bendetowicz ◽  
Elisabeth Pacaud ◽  
Suzette Béguin ◽  
André Uzan ◽  
H Coenraad Hemker
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Low Molecular Weight Heparin ◽  
Anticoagulant Activity ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Molecular Weights ◽  
Thrombin Inhibition ◽  
Specific Catalytic Activity ◽  
The Relationship

SummaryA low molecular weight heparin (enoxaparin, mean molecular weight ~ 4,400) was separated by gel chromatography into eight different fractions with a narrow distribution around the following mean molecular weights: 1,800, 2,400, 2,900, 4,200, 6,200, 8,600, 9,800 and 11,000. We compared the influence of enoxaparin on the generation of thrombin in plasma to that of the eight fractions.We determined: a) the % of material with high affinity to antithrombin III (HAM) and the % of HAM above the critical chainlength necessary to allow for thrombin inhibition (ACLM), b) the specific catalytic activity on the decay of endogenous thrombin, and c) the inhibition of over-all thrombin formation in the extrinsic and the intrinsic pathway. From b and c we calculated the inhibition of prothrombin conversion in these pathways.We found that a) there is a gradual decrease of the HAM fraction with decreasing molecular weight; b) the specific catalytic activity for the inactivation of thrombin does not vary significantly between the fractions when expressed in terms of ACLM; c) the potency to inhibit prothrombin conversion does not vary significantly between the fractions when expressed in terms of HAM.

scholarly journals Binding to antithrombin of heparin fractions with different molecular weights

1981 ◽  
Vol 193 (2) ◽  
pp. 427-433 ◽  
Author(s):  
Ȧke Danielsson ◽  
Ingemar Björk
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Binding Constants ◽  
Gel Chromatography ◽  
Molecular Weights ◽  
High Affinity ◽  
Heparin Fractions ◽  
Fluorescence Titrations ◽  
In The Beginning ◽  
Difference Absorption

The interaction between bovine antithrombin, a plasma proteinase inhibitor, and heparin species of different molecular weights was studied. A commercial heparin preparation was divided by gel chromatography into a number of fractions with average molecular weights ranging from 6000 to 34700. Each of these fractions was further fractionated by affinity chromatography on matrix-bound antithrombin. In the latter procedure, those heparin fractions that had molecular weights lower than about 14000 were separated into three peaks. The material in the first of these was not adsorbed on the column, and the other two peaks corresponded to the low-affinity and high-affinity peaks described previously. In contrast, high-molecular-weight heparin samples gave only the low-affinity and high-affinity fractions. U.v. difference absorption studies showed that the non-adsorbed heparin fraction bound to antithrombin in solution with a binding constant at physiological ionic strength only slightly lower than that of low-affinity heparin. The division between the two fractions thus is arbitrary and only dependent on the conditions selected for the affinity-chromatography experiment. Stoicheiometries and binding constants for the binding of several high-affinity heparin species to antithrombin were determined by fluorescence titrations. High-affinity heparin fractions of equal elution positions in the beginning of the peaks of the affinity chromatographies, but with different molecular weights, showed stoicheiometries that were not experimentally distinguishable from 1:1 and also had no appreciable differences in binding constants. However, the anticoagulant activities, calculated on a molar basis, of these fractions increased markedly with molecular weight, a behaviour that thus cannot be explained by differences in the binding of the fractions to antithrombin. In contrast, high-affinity samples of similar molecular weights, which were eluted at increasing ionic strengths from matrix-linked antithrombin, were found to have an increasing proportion of chains with two binding sites for antithrombin and also to have progressively higher binding constants. These binding properties at least partly explain the increasing anticoagulant activities that were observed for these fractions.

scholarly journals Effect of powdered spice treatments on mycelial growth, sporulation and production of aflatoxins by toxigenic fungi

2004 ◽  
Vol 28 (4) ◽  
pp. 856-862 ◽  
Author(s):  
Sára Maria Chalfoun ◽  
Marcelo Cláudio Pereira ◽  
Mario Lúcio V. Resende ◽  
Caroline Lima Angélico ◽  
Rozane Aparecida da Silva
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Flavus ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Culture Media ◽  
The Other ◽  
Toxigenic Fungi ◽  
Order Promising ◽  
Fungistatic Effect

The effect of ten powdered spice plants was evaluated at the concentration of 1, 2, 3 and 4% to observe the mycelial growth and sporulation of Aspergillus niger and Eurotium repens. The spices were added to the culture media PDA and CYA20S. Clove completely inhibited the mycelial growth of the tested fungi. The other spices: cinnamon, garlic, thyme, mint, anis, oregano and onion were, in a decreasing order, promising antifungals. Bay leaf and basil did not show a pronounced fungistatic effect. The antitoxigenic potential of the spices was tested against one aflatoxin-producing strain of AspergiIIus flavus. The spices were tested at the same concentrations previously mentioned and were added to the culture medium YES, appropriate for the production of those metabolites. Clove completely inhibited the mycelial growth of Aspergillus flavus. Cinnamon and anis totally inhibited the production of Bl and B2 aflatoxin. Both bay leaf and basil inhibited the synthesis of aflatoxin starting from the concentration of 2%. The other spices did not have a pronounced antiaflatoxigenic effect.

A Labile CO2-Fixing Enzyme Complex in Spinach Chloroplasts

1972 ◽  
Vol 27 (8) ◽  
pp. 925-932 ◽  
Author(s):  
Bruno Müller
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Phosphoglycerate Kinase ◽  
Gel Chromatography ◽  
Enzyme Complex ◽  
Molecular Weights ◽  
Spinach Chloroplasts ◽  
Reversible Dissociation ◽  
Glyceraldehyde Phosphate Dehydrogenase ◽  
Ribulose Diphosphate Carboxylase

Activity and activation of ribulose 5-phosphate kinase, ribulose diphosphate carboxylase, phosphoglycerate kinase, and the NADP- and NAD-dependent glyceraldehyde phosphate dehydrogenases from isolated diloroplasts were traced in the course of differential ultracentrifugation. Activation of some of these enzymes was carried out by incubation with NADPH2 or ATP. Activity of ribulose diphosphate carboxylase could be increased 2,4-fold by incubation with NADPH2 while phosphoglycerate kinase could not be activated.The degree of activation of the NADP-specific glyceraldehyde phosphate dehydrogenase and ribulose phosphate kinase was correlated with the velocity of sedimentation. Enzymes, which could be activated manifold, sedimented more quickly. Two fractions could be obtained after ultracentri fugation: the sedimented fraction could be highly activated while the fraction in the supernatant could not.It was shown by gel chromatography with Sephadex for the NADP-specific glyceraldehyde phosphate dehydrogenase and ribulose phosphate kinase that the enzyme fractions which could be greatly activated had molecular weights of at least 400 000. In contrast, the enzyme fraction which could not be activated had a molecular weight of 50 000 for the ribulose phosphate kinase and of 240 000 for the glyceraldehyde phosphate dehydrogenases.Results are discussed in the way that a reversible dissociation of a labile enzyme complex takes place between ribulose phosphate kinase, glyceraldehyde phosphate dehydrogenases, and ribulose diphosphate carboxylase. Enzyme activity changes with the state of aggregation. The dissociated enzymes have higher activity than the complexed ones. Dissociation can be performed by ATP and NADPH2, which are assumed to be the physiological regulators, and by unphysiological means as dilution and high salt concentrations.

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