Chromatographic fractionation and molecular mass characterization of Cercidium praecox (Brea) gum

2016 ◽  
Vol 96 (13) ◽  
pp. 4345-4350 ◽  
Author(s):  
Virginia Castel ◽  
Svetlana Zivanovic ◽  
Juan L Jurat-Fuentes ◽  
Liliana G Santiago ◽  
Amelia C Rubiolo ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Chromatographic Fractionation ◽  
Cercidium Praecox

Characterization of dissolved material during the initial phase of softwood kraft pulping

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 37-43 ◽  
Author(s):  
HANNU PAKKANEN ◽  
TEEMU PALOHEIMO ◽  
RAIMO ALÉN
Keyword(s):  
Mass Transfer ◽  
Molecular Mass ◽  
Initial Phase ◽  
Degradation Products ◽  
Kraft Pulping ◽  
Reaction Products ◽  
Cooking Temperature ◽  
Molecular Masses ◽  
Aliphatic Carboxylic Acids

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.

scholarly journals Characterization of five new low-molecular-mass trypsin inhibitors from white mustard (Sinapis alba L.) seed

2000 ◽  
Vol 267 (21) ◽  
pp. 6486-6492 ◽  
Author(s):  
Margherita Ruoppolo ◽  
Angela Amoresano ◽  
Piero Pucci ◽  
Stefano Pascarella ◽  
Fabio Polticelli ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Sinapis Alba ◽  
Trypsin Inhibitors ◽  
White Mustard ◽  
Sinapis Alba L

scholarly journals Identification and characterization of Sulfolobus solfataricusD-gluconate dehydratase: a key enzyme in the non-phosphorylated Entner–Doudoroff pathway

2005 ◽  
Vol 387 (1) ◽  
pp. 271-280 ◽  
Author(s):  
Seonghun KIM ◽  
Sun Bok LEE
Keyword(s):  
Molecular Mass ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Genome Database ◽  
Sds Page ◽  
Key Enzyme ◽  
Bivalent Metal Ions ◽  
Ammonium Sulphate Fractionation ◽  
Identification And Characterization

The extremely thermoacidophilic archaeon Sulfolobus solfataricus utilizes D-glucose as a sole carbon and energy source through the non-phosphorylated Entner–Doudoroff pathway. It has been suggested that this micro-organism metabolizes D-gluconate, the oxidized form of D-glucose, to pyruvate and D-glyceraldehyde by using two unique enzymes, D-gluconate dehydratase and 2-keto-3-deoxy-D-gluconate aldolase. In the present study, we report the purification and characterization of D-gluconate dehydratase from S. solfataricus, which catalyses the conversion of D-gluconate into 2-keto-3-deoxy-D-gluconate. D-Gluconate dehydratase was purified 400-fold from extracts of S. solfataricus by ammonium sulphate fractionation and chromatography on DEAE-Sepharose, Q-Sepharose, phenyl-Sepharose and Mono Q. The native protein showed a molecular mass of 350 kDa by gel filtration, whereas SDS/PAGE analysis provided a molecular mass of 44 kDa, indicating that D-gluconate dehydratase is an octameric protein. The enzyme showed maximal activity at temperatures between 80 and 90 °C and pH values between 6.5 and 7.5, and a half-life of 40 min at 100 °C. Bivalent metal ions such as Co2+, Mg2+, Mn2+ and Ni2+ activated, whereas EDTA inhibited the enzyme. A metal analysis of the purified protein revealed the presence of one Co2+ ion per enzyme monomer. Of the 22 aldonic acids tested, only D-gluconate served as a substrate, with Km=0.45 mM and Vmax=0.15 unit/mg of enzyme. From N-terminal sequences of the purified enzyme, it was found that the gene product of SSO3198 in the S. solfataricus genome database corresponded to D-gluconate dehydratase (gnaD). We also found that the D-gluconate dehydratase of S. solfataricus is a phosphoprotein and that its catalytic activity is regulated by a phosphorylation–dephosphorylation mechanism. This is the first report on biochemical and genetic characterization of D-gluconate dehydratase involved in the non-phosphorylated Entner–Doudoroff pathway.

scholarly journals The Presence and Characterization of a virF Gene on Agrobacterium vitis Ti Plasmids

1998 ◽  
Vol 11 (5) ◽  
pp. 429-433 ◽  
Author(s):  
B. Schrammeijer ◽  
J. Hemelaar ◽  
P. J. J. Hooykaas
Keyword(s):  
Amino Acids ◽  
Agrobacterium Tumefaciens ◽  
Molecular Mass ◽  
Promoter Region ◽  
Consensus Sequence ◽  
Tumor Formation ◽  
Nicotiana Glauca ◽  
Agrobacterium Vitis ◽  
Ti Plasmids

Octopine and nopaline strains of Agrobacterium tumefaciens differ in their ability to induce tumors on Nicotiana glauca. The presence of a virF locus on the octopine Ti plasmid makes N. glauca a host plant for these strains, indicating that the VirF protein is a host-range determinant. Here we show the presence of a virF locus not only on the Agrobacterium vitis octopine/cucumopine plasmids pTiAg57 and pTiTm4, but also on the nopaline Ti plas-mids pTiAT1, pTiAT66a, and pTiAT66b. On the octopine Ti plasmids from A. tumefaciens the virF gene is located between the virE locus and the left border of the T-region. In contrast, the virF gene on Ti plasmids of A. vitis is located at the very left end of the vir-region near the virA locus. The virF gene of pTiAg57 has been sequenced and codes for a protein of 202 amino acids with a molecular mass of 22,280 Da. Comparison showed that the virF gene from A. vitis strain Ag57 is almost identical to that from A. tumefaciens octopine strains. The transcription of the pTiAg57 virF is inducible by the plant phenolic compound acetosyringone through the presence of a vir-box consensus sequence in its promoter region. The VirF protein from pTiAg57 can complement octopine A. tumefaciens strains deleted for virF as shown by tumor formation on N. glauca.

scholarly journals Characterization of [3H]palmitate- and [3H]ethanolamine-labelled proteins in the multicellular parasitic trematode Schistosoma mansoni

1988 ◽  
Vol 254 (2) ◽  
pp. 419-426 ◽  
Author(s):  
P M Wiest ◽  
E J Tisdale ◽  
W L Roberts ◽  
T L Rosenberry ◽  
A A F Mahmoud ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Molecular Mass ◽  
Gel Electrophoresis ◽  
Free Amino ◽  
Protein Modification ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Reductive Methylation ◽  
Amide Linkage

Biosynthetic labelling experiments with cercariae and schistosomula of the multicellular parasitic trematode Schistosoma mansoni were performed to determine whether [3H]palmitate or [3H]ethanolamine was incorporated into proteins. Parasites incorporated [3H]palmitate into numerous proteins, as judged by SDS/polyacrylamide-gel electrophoresis and fluorography. The radiolabel was resistant to extraction with chloroform, but sensitive to alkaline hydrolysis, indicating the presence of an ester bond. Further investigation of the major 22 kDa [3H]palmitate-labelled species showed that the label could be recovered in a Pronase fragment which bound detergent and had an apparent molecular mass of 1200 Da as determined by gel filtration on Sephadex LH-20. Schistosomula incubated with [3H]ethanolamine for up to 24 h incorporated this precursor into several proteins; labelled Pronase fragments recovered from the three most intensely labelled proteins were hydrophilic and had a molecular mass of approx. 200 Da. Furthermore, reductive methylation of such fragments showed that the [3H]ethanolamine bears a free amino group, indicating the lack of an amide linkage. We also evaluated the effect of phosphatidylinositol-specific phospholipase C from Staphylococcus aureus: [3H]palmitate-labelled proteins of schistosomula and surface-iodinated proteins were resistant to hydrolysis with this enzyme. In conclusion, [3H]palmitate and [3H]ethanolamine are incorporated into distinct proteins of cercariae and schistosomula which do not bear glycophospholipid anchors. The [3H]ethanolamine-labelled proteins represent a novel variety of protein modification.

scholarly journals Characterization of Biosynthetic Enzymes for Ectoine as a Compatible Solute in a Moderately Halophilic Eubacterium, Halomonas elongata

1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Mass ◽  
Optimum Temperature ◽  
Sds Page ◽  
Halomonas Elongata ◽  
Optimum Ph

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.

scholarly journals Purification and characterization of a thermostable ADP-glucose pyrophosphorylase from Thermus caldophilus GK-24

1996 ◽  
Vol 319 (3) ◽  
pp. 977-983 ◽  
Author(s):  
Jeong Heon KO ◽  
Cheorl Ho KIM ◽  
Dae-Sil LEE ◽  
Yu Sam KIM
Keyword(s):  
Molecular Mass ◽  
Specific Activity ◽  
Gel Filtration ◽  
Higher Plant ◽  
Sds Page ◽  
Thermus Caldophilus ◽  
Internal Peptide ◽  
Adp Glucose Pyrophosphorylase ◽  
Fructose 1,6 Bisphosphate

An extremely thermostable ADP-glucose pyrophosphorylase (AGPase) has been purified from Thermus caldophilus GK-24 to homogeneity by chromatographic methods, including gel filtration and ion-exchange and affinity chromatography. The specific activity of the enzyme was enriched 134.8-fold with a recovery of 10.5%. The purified enzyme was a single band by SDS/PAGE with a molecular mass of 52 kDa. The homotetrameric structure of the native enzyme was determined by gel filtration analysis, which showed a molecular mass of 230 kDa on a Superose-12 column, indicating that the structure of the enzyme is different from the heterotetrameric structures of higher-plant AGPases. The enzyme was most active at pH 6.0. The activity was maximal at 73–78 °C and its half-life was 30 min at 95 °C. Kinetic and regulatory properties were characterized. It was found that AGPase activity could be stimulated by a number of glycolytic intermediates. Fructose 6-phosphate, fructose 1,6-bisphosphate, phenylglyoxal and glucose 6-phosphate were effective activators, of which fructose 1,6-bisphosphate was the most effective. The enzyme was inhibited by phosphate, AMP or ADP. ATP and glucose 1-phosphate gave hyperbolic-shaped rate-concentration curves in the presence or absence of activator. A remarkable aspect of the amino acid composition was the existence of the hydrophobic and Ala+Gly residues. The N-terminal and internal peptide sequences were determined and compared with known sequences of various sources. It was apparently similar to those of AGPases from other bacterial and plant sources, suggesting that the enzymes are structurally related.

Preparation and Characterization of JP-10 Gel Propellants with Tris-Urea Low-Molecular Mass Gelators

2016 ◽  
Vol 41 (2) ◽  
pp. 212-216 ◽  
Author(s):  
Xian Ping Qiu ◽  
Ai Min Pang ◽  
Feng Jin ◽  
Wei Wei ◽  
Ke Hai Chen ◽  
...  
Keyword(s):  
Molecular Mass
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