scholarly journals A study of the coenzyme-binding characteristics of rabbit muscle l-glycerol 3-phosphate dehydrogenase

1974 ◽  
Vol 143 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Philip Bentley ◽  
F. Mark Dickinson
Keyword(s):  
Second Order ◽  
Rabbit Muscle ◽  
Velocity Constant ◽  
Binding Characteristics ◽  
Temperature Range ◽  
Coenzyme Binding ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Ph Range

1. The binding of NAD+and NADH to glycerol 3-phosphate dehydrogenase was studied in the pH range 6.0–9.0 at 25°C and in the temperature range 16–43°C at pH7.0. 2. The second-order velocity constants for the combination of NADH with the enzyme in the pH range 6.0–9.0 and for the combination of NAD+with the enzyme at pH6.0 were determined. 3. The velocity constant for the dissociation of the enzyme–NAD+complex at pH6.0 was measured.

scholarly journals A study of the kinetics and mechanism of rabbit muscle l-glycerol 3-phosphate dehydrogenase

1974 ◽  
Vol 143 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Philip Bentley ◽  
F. Mark Dickinson
Keyword(s):  
Basic Mechanism ◽  
Kinetics And Mechanism ◽  
Dihydroxyacetone Phosphate ◽  
Rabbit Muscle ◽  
Kinetics Of Oxidation ◽  
Mechanism Of Catalysis ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Ph Range ◽  
Kinetics Of

1. The kinetics of oxidation of l-glycerol 3-phosphate by NAD+and of reduction of dihydroxyacetone phosphate by NADH catalysed by rabbit muscle glycerol 3-phosphate dehydrogenase were studied over the range pH6–9. 2. The enzyme was found to catalyse the oxidation of glyoxylate by NAD+at pH8.0 and the kinetics of this reaction were also studied. 3. The results are consistent with a compulsory mechanism of catalysis for glycerol 3-phosphate oxidation and dihydroxyacetone phosphate reduction in the intermediate regions of pH, but modifications to the basic mechanism are required to fully explain results at the extremes of the pH range, with these substrates and for glyoxylate oxidation at pH8.0.

scholarly journals Marisediminicola antarctica gen. nov., sp. nov., an actinobacterium isolated from the Antarctic

2010 ◽  
Vol 60 (11) ◽  
pp. 2535-2539 ◽  
Author(s):  
Hui-Rong Li ◽  
Yong Yu ◽  
Wei Luo ◽  
Yin-Xin Zeng
Keyword(s):  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Intertidal Sediment ◽  
Rrna Gene ◽  
Optimum Growth ◽  
Temperature Range ◽  
Zhongshan Station ◽  
Diamino Acid ◽  
Ph Range ◽  
The Antarctic

Strain ZS314T was isolated from a sandy intertidal sediment sample collected from the coastal area off the Chinese Antarctic Zhongshan Station, east Antarctica (6 ° 22′ 13″ S 7 ° 21′ 41″ E). The cells were Gram-positive, motile, short rods. The temperature range for growth was 0–26 °C and the pH for growth ranged from 5 to 10, with optimum growth occurring within the temperature range 18–23 °C and pH range 6.0–8.0. Growth occurred in the presence of 0–6 % (w/v) NaCl, with optimum growth occurring in the presence of 2–4 % (w/v) NaCl. Strain ZS314T had MK-10 as the major menaquinone and anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 as major fatty acids. The cell-wall peptidoglycan type was B2β with ornithine as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The genomic DNA G+C content was approximately 67 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain ZS314T represents a new lineage in the family Microbacteriaceae. On the basis of the phylogenetic analyses and phenotypic characteristics, a new genus, namely Marisediminicola gen. nov., is proposed, harbouring the novel species Marisediminicola antarctica sp. nov. with the type strain ZS314T (=DSM 22350T =CCTCC AB 209077T).

Studies of Chromium Removal from Tannery Effluents by Dead Streptomyces Rimosus

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar
Keyword(s):  
Fractional Power ◽  
Kinetic Studies ◽  
Second Order ◽  
Order Kinetic ◽  
Streptomyces Rimosus ◽  
Tannery Effluents ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ph Range

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.

scholarly journals Influence of hydrotalcite preparation conditions on its physico-chemical properties

2019 ◽  
Vol 12 (1) ◽  
pp. 119-126
Author(s):  
Miroslava Mališová ◽  
Michal Horňáček ◽  
Pavol Hudec ◽  
Jozef Mikulec ◽  
Vladimír Jorík ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Chemical Properties ◽  
Synthesis Temperature ◽  
Optimal Synthesis ◽  
Preparation Process ◽  
Optimal Conditions ◽  
Temperature Range ◽  
Preparation Conditions ◽  
Physico Chemical ◽  
Ph Range

Abstract The aim of the research was to prepare and characterize hydrotalcite synthesized under different preparation conditions. The most common hydrotalcite preparation is the co-precipiaton method. The preparation process strongly influences the catalytic properties of hydrotalcite; therefore, optimal conditions have to be determined. During the study, seven samples of the catalyst were prepared in the pH range from 8 to 12 and the synthesis temperature range from 25 to 55 °C. Based on several catalyst properties, optimal synthesis pH 10 was found. Ideal temperature of the preparation was determined to be 35 °C, but the temperature does not have a significant effect on the catalyst properties.

scholarly journals Production and partial characterization of a crude cold-active cellulase (CMCase) from Bacillus mycoides AR20-61 isolated from an Alpine forest site

2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Elisa Steiner ◽  
Rosa Margesin
Keyword(s):  
Enzyme Activity ◽  
Bacterial Growth ◽  
Enzyme Production ◽  
Crude Enzyme ◽  
Cultivation Temperature ◽  
Bacillus Mycoides ◽  
Temperature Range ◽  
Alpine Forest ◽  
Cold Active ◽  
Ph Range

Abstract Purpose To evaluate the production of a cold-active CMCase (endoglucanase) by Bacillus mycoides AR20-61 isolated from Alpine forest soil and to characterize the crude enzyme. Methods After studying the effect of cultivation parameters (medium composition, temperature, NaCl concentration, pH) on bacterial growth and enzyme production, the crude enzyme was characterized with regard to the effect of pH, temperature, and inhibitors on enzyme activity and stability. Result Optimum growth and enzyme production occurred at 20–25 °C, pH 7, and 1–1.5% (w/v) CMC. Despite high biomass production over the whole growth temperature range (10–35 °C), enzyme production was low at 10 and 35 °C. CMC concentration had a minor effect on growth, independent of the growth temperature, but a significant effect on CMCase production at temperatures ≥ 20 °C. The crude enzyme was active over a broad temperature range (0–60 °C); the apparent optimum temperature for activity was at 40–50 °C. The cultivation temperature influenced the effect of temperature on enzyme activity and stability. A significantly higher thermosensitivity of the enzyme produced at a cultivation temperature of 10 °C compared to that produced at 25 °C was noted at 50 and 65 °C. The enzyme was highly active over a pH range of 4–6 and showed optimum activity at pH 5. No activity was lost after 60 min of incubation at 30 °C and pH 4–9. The CMCase was resistant against a number of monovalent and divalent metal ions, metal-chelating agents, and phenol. Conclusion The CMCase produced by the studied strain is characterized by high activities in the low temperature range (down to 0 °C) and acidic pH range, high stability over a broad pH range, and high resistance against a number of effectors. Our results also demonstrate the different, independent roles of temperature in bacterial growth, enzyme production, nutrient requirements during enzyme production, and enzyme characteristics regarding thermosensitivity, which has not yet been described for cellulases.

scholarly journals Re-evaluation of the glycerol-3-phosphate dehydrogenase/l-lactate dehydrogenase enzyme system. Evidence against the direct transfer of NADH between active sites

1991 ◽  
Vol 278 (3) ◽  
pp. 875-881 ◽  
Author(s):  
S P J Brooks ◽  
K B Storey
Keyword(s):  
Lactate Dehydrogenase ◽  
Active Sites ◽  
Reaction Rate ◽  
Experimental Results ◽  
Transfer Model ◽  
Rabbit Muscle ◽  
Direct Transfer ◽  
Theoretical Predictions ◽  
Glycerol 3 Phosphate Dehydrogenase

An investigation of the direct transfer of metabolites from rabbit muscle L-lactate dehydrogenase (LDH, EC 1.1.1.27) to glycerol-3-phosphate dehydrogenase (GPDH, EC 1.1.1.8) revealed discrepancies between theoretical predictions and experimental results. Measurements of the GPDH reaction rate at a fixed NADH concentration and in the presence of increasing LDH concentrations gave experimental results similar to those previously obtained by Srivastava, Smolen, Betts, Fukushima, Spivey & Bernhard [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6464-6468]. However, a mathematical solution of the direct-transfer-mechanism equations as described by Srivastava et al. (1989) showed that the direct-transfer model did not adequately describe the experimental behaviour of the reaction rate at increasing LDH concentrations. In addition, experiments designed to measure the formation of an LDH4.NADH.GPDH2 complex, predicted by the direct-transfer model, indicated that no significant formation of tertiary complex occurred. An examination of other kinetic models, developed to describe the LDH/GPDH/NADH system better, revealed that the experimental results may be best explained by assuming that free NADH, and not E1.NADH, is the sole substrate for GPDH. These results suggest that direct transfer of NADH between rabbit muscle LDH and GPDH does not occur in vitro.

Isolation and some properties of extracellular heat-stable lipases fromPseudomonas fluorescensstrain AFT 36

1983 ◽  
Vol 50 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Patrick F. Fox ◽  
Leszek Stepaniak
Keyword(s):  
Phosphate Buffer ◽  
Lipolytic Activity ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Lipase Production ◽  
Maximum Activity ◽  
Temperature Range ◽  
Milk Serum ◽  
Heat Stable ◽  
Ph Range

SummaryAeration increased the growth and lipase production in milk byPseudomonas fluorescensstrain AFT 36, isolated from refrigerated bulk milk. A heat-stable lipase was isolated from a shaken milk culture of this microorganism by DEAE-chromatography and gel filtration in Sepharose 6B. The lipase-rich fraction from DEAE cellulose contained 3 lipases that were separated by gel filtration; only the principal lipase, which represented ∼ 71 % of total lipolytic activity, was characterized. The purified enzyme showed maximum activity on tributyrin at pH 8·0 and 35 °C; it had aKmon tributyrin of 3·65 mM. and was inhibited by concentrations of substrate > ∼ 17 mM. The enzyme was very stable over the pH range 6–9; it was relatively heat-labile in phosphate buffer in the temperature range 60–80 °C, where it was stabilized significantly by Ca2+. It was, however, very stable at 100–150 °C: theDvalues at 150 °C were ∼ 22 s and 28 s in phosphate buffer and synthetic milk serum respectively; the correspondingZvalues in the temperature range 100–150 °C were ∼ 40 and ∼ 42 °C and theEafor inactivation were 7·65 × 104J mol-1and 6·97 × 104J mol-1respectively.

Oxidation of bisphenol A by permanganate: reaction kinetics and removal of estrogenic activity

2013 ◽  
Vol 67 (8) ◽  
pp. 1867-1872 ◽  
Author(s):  
Jingjing Yang ◽  
Gang Wen ◽  
Ji Zhao ◽  
Xiaoling Shao ◽  
Jun Ma
Keyword(s):  
Bisphenol A ◽  
Reaction Kinetics ◽  
Estrogenic Activity ◽  
Complete Removal ◽  
Order Rate Constant ◽  
Second Order ◽  
Specific Rate ◽  
Order Rate ◽  
Ph Dependency ◽  
Ph Range

The kinetics for reaction between bisphenol A (BPA) and permanganate was examined over pH range of 5.0–9.9 and the estrogenic activity of aqueous BPA solution after oxidation was assessed by yeast two-hybrid assay. Reaction kinetics follows the second-order rate law, with the apparent second-order rate constant of 15.1 ± 1.1 M−1s−1 at pH 6.0 and 25°C and the activation energy of 48.7 kJ/mol. The kinetics exhibits pH dependency and the specific rate constants related to speciation of BPA are 50 ± 28 M−1s−1, 9.6 (±0.6) × 103 M−1s−1 and 1.4 (±0.1) × 104 M−1s−1 for BPA, BPA− and BPA2−, respectively. The results of the estrogenic/antiestrogenic activity test show that there is a hysteresis for the removal of estrogenic activity of aqueous BPA solution at pH 7.3. Removal of BPA is completed in 10 min, but complete removal of estrogenic activity requires a further 20 min.

Nickel Loss during Iron Precipitation and Product Characterization

2011 ◽  
Vol 402 ◽  
pp. 293-296
Author(s):  
Kai Wang ◽  
Jian Li ◽  
R.G. McDonald ◽  
R.E. Browner
Keyword(s):  
Calcium Carbonate ◽  
Magnesium Oxide ◽  
Precipitation Process ◽  
Nickel Sulphate ◽  
Temperature Range ◽  
Iron Precipitation ◽  
Product Characterization ◽  
Ph Range ◽  
Iron Precipitates

In this study, the iron precipitation and associated nickel loss from synthetic ferric and nickel sulphate solutions were investigated. Two types of common neutralizing agents, magnesium oxide and calcium carbonate were applied in the investigation. The results indicated that pH and temperature had significant impacts on nickel loss during the iron precipitation process, whereas the type of neutralizing agents had little effect. It was found that increasing in pH and temperature resulted in more nickel loss in the pH range of 2 to 4 and temperature range of 25 to 85 °C. Mineralogical examination by XRD indicated that the iron precipitates were combinations of schwertmannite, ferrihydrite and goethite. In addition, more crystalline goethite was formed from the ferric solutions when no nickel was present, indicating that nickel might play a role in inhabiting the crystallization of goethite.

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