Search results for "WEIGHT"

Preparative separation of proteins and enzymes in the mean molecular-weight range of 10,000–100,000 LiChrosorb diol® packing by high-performance size…

1979

Abstract LiChrossorb Diol® packing has been to be well-suited for the separation of proteins and enzymes according to a size-exclusion mechanism in a mean molecular-weight (MW) range between 10,000 and 100,000. Loadability of a small bore column of 6 mm I.D. (A) and a large-bore column of 23.5 mm I.D. (B), both of 250 mm in length, were examined. Defining a 20% decrease of the number of theoretical plates as loadability limit the volume load at constant mass of chymotrypsinogen as representative test solute was ≈ 100 μl for column (A) and 1500 μl for column B at 0.78 · 10-5 g/g of packing for column A and 0.78 · 10-6 g/g of packing for column B, respectively. Mass load to constant injection…

Isolation and characterization of a chlorogenic acid esterase from Aspergillus niger.

1980

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split…

Purification of rat liver epoxide hydratase to apparent homogeneity.

1975

Epoxide hydratase (EC 4.2.1.63) is a microsomal enzyme which catalyses the conversion of epoxides to trans-dihydrodiols. Epoxides, produced by the action of microsomal monooxygenases (EC 1.14.1.1) from aromatic and olefinic compounds, are thought to be responsible for many of the harinful effects of polycyclic hydrocarbons and related compounds. Thus epoxide hydratase, together with glutathione 9transferases, (EC 2.5.1.18) may play an important role in the removal of carcinogenic and cytotoxic metabolites (for reviews see [l-3]). It has been reported [4,5] that dihydrodiols formed from some polycyclic hydrocarbons (benz(a)anthracene and benzo(a)pyrene) are reactivated by the microsomal mono…

Biochemical characterization of two functional human liver acyl-CoA oxidase isoforms 1a and 1b encoded by a single gene

2007

Abstract Human acyl-CoA oxidase 1 (ACOX1) is a rate-limiting enzyme in peroxisomal fatty acids β-oxidation and its deficiency is associated with a lethal, autosomal recessive disease, called pseudoneonatal-adrenoleukodystrophy. Two mRNA variants, transcribed from a single gene encode ACOX1a or ACOX1b isoforms, respectively. Recently, a mutation in a splice site has been reported [H. Rosewich, H.R. Waterham, R.J. Wanders, S. Ferdinandusse, M. Henneke, D. Hunneman, J. Gartner, Pitfall in metabolic screening in a patient with fatal peroxisomal β-oxidation defect, Neuropediatrics 37 (2006) 95–98.], which results in the defective peroxisomal fatty acids β-oxidation. Here, we show that these mRNA…

Effect of iron and aeration on superoxide dismutase and catalase activity of PHB-producing Azotobacter chroococcum

2009

Abstract The effect of aeration level and iron concentration on Azotobacter chroococcum 23 growth, PHB accumulation and antioxidative enzyme activities was investigated in shake flask experiments. Biomass yield and carbon source conversation coefficients increased in the presence of iron in the growth medium and under decreased aeration. The highest biomass production was observed for the culture grown in a medium with 36 μM of initial iron concentration and moderate aeration level. The highest PHB accumulation level (70–72% from cell dry weight) under our experimental conditions was observed at decreased aeration in the growth medium with 180 μM of initial iron concentration. Results obtai…

Molekulargewichtsverteilungen einiger emulsionspolymerisate von styrol

1965

An einigen unter normalen Bedingungen hergestellten Emulsionspolymerisaten werden die Verteilungen durch Fallungschromatographie bestimmt. Die Uneinheitlichkeit ist erheblich hoher als bei unter homogenen Bedingungen hergestellten Polymerisaten, und die Verteilungskurven weisen einige Besonderheiten auf. Einige Schlusse uber die Kinetik der Emulsionspolymerisation konnen daraus gezogen werden. Vergleichende Viskositats- und Lichtstreuungsmessungen im Bereich der Molekulargewichte 106 bis 107 ergeben, das die [η]-M-Beziehung bei Emulsionspolymerisaten und homogen polymerisierten Polystyrolen innerhalb der Fehlergrenzen ubereinstimmt. The molecular-weight distributions of several polymers pre…

Calculation of the molecular masses of two newly synthesized thermostable enzymes isolated from thermophilic microorganisms

1995

Two thermostable enzymes synthesized by thermophilic microorganisms were isolated and purified. A thermostable beta-galactosidase was produced in a continuous fermentation process by Bacillus stearothermophilus TP 32 as an intracellular enzyme. After applying different concentration procedures the raw extract enzyme was prepurified on a Sephadex G-200 size exclusion column. The isolated beta-galactosidase fraction was then separated with HPLC on a TSK G 3000 SW size exclusion column to determine the molecular mass based on calibration curves of standard proteins. The other enzyme, a thermostable protease, was synthesized by Bacillus stearothermophilus TP 26 as an extracellular enzyme. After…

Activities of Two Peptidases in Resting and Germinating Seeds of Scots Pine, Pinus sylvestris

1975

Extracts prepared from resting seeds of Scots pine, Pinus sylvestris L., rapidly hydrolysed two peptides, Leu–Tyr and Ala–Gly, at pH 8.6 and 7.8, respectively. In gel chromatography on Sephadex G-100 the two activities were eluted as separate peaks, which indicates that they are due to two different peptidases. The seeds were allowed to germinate at 20°C, the activities of the two enzymes were assayed separately on extracts from the endosperm and seedling tissues at different stages of germination, and compared with corresponding changes in dry weight and total nitrogen. Both enzyme activities were relatively high in the endosperm of resting seeds, and they increased about 2- and 3-fold dur…

Phase Behavior ofn-Alkyl-substituted Polysilanes

2007

Cementing agents involved in the macro- and microaggregation of a Mediterranean shrubland soil under laboratory heating

2014

The heating effect on aggregation and cementing agents of a Mediterranean soil was studied in two fractions (macro- and microaggregates) in different environments: under Quercus coccifera soil (UQ), under Rosmarinus officinalis soil (UR) and between plants or bare soil (BS). Samples were heated under laboratory conditions at different temperatures (220, 380, 500, 750 and 1000. °C) to establish their effects on the studied soil properties by comparison with unheated control samples (25. °C). Increasing temperature treatments caused significant changes in most soil variables. In both soil fractions, the presence of vegetation contributed to increase of the soil organic matter (SOM) content, w…