Gold nanoparticle–protein conjugate dually-responsive to pH and temperature for modulation of enzyme activity

2019 ◽  
Vol 7 (20) ◽  
pp. 3260-3267
Author(s):  
Ya Sun ◽  
Zhenhua Li ◽  
Jingxian Wu ◽  
Zhiqiang Wang ◽  
Yishi Dong ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Gold Nanoparticle ◽  
Full Range ◽  
Protein Polymer ◽  
Temperature Conditions ◽  
Dual Responsive ◽  
Polymer Conjugate ◽  
Protein Conjugate

The enzymatic activity of the dual-responsive gold nanoparticle–protein–polymer conjugate can be modulated almost in a full range under different pH and temperature conditions.

Gold Nanoparticle-Protein Conjugate Dually-Responsive to pH and Temperature for Modulation of Enzyme Activity

2019 ◽  
Author(s):  
Ya Sun ◽  
Zhenhua Li ◽  
Jingxian Wu ◽  
Zhiqiang Wang ◽  
Yishi Dong ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Gold Nanoparticle ◽  
Protein Conjugate

Pengaruh Penambahan Molases Pada Kulit Pisang Kapendis Untuk Media Produksi Xilanase B.Stearothermophillus DSM 22

2019 ◽  
Vol 15 (3) ◽  
Author(s):  
Trismillah
Keyword(s):  
Enzyme Activity ◽  
Ammonium Sulfate ◽  
Banana Peel ◽  
Partial Purification ◽  
Temperature Conditions ◽  
Cavendish Banana ◽  
Working Volume ◽  
Initial Ph ◽  
Xylanase Enzyme

Cavendish banana peel can be used as a substitute for the expensive xylan, while molasses than as a source of carbon as well as nitrogen, minerals and nutrients needed for the growth of microbes that can produce the enzyme. Xylanase produced from Bacillus stearothermopillus DSM 22, using media cavendish banana peels with the addition of molasses 1%, 2%, and 3%. Fermentation is done in a shaker incubator at 550C temperature conditions, initial pH 8, and 250 rpm agitation. The result showed the highest enzyme activity of 4,14 ± 0,16 U/mL min., on the addition 2% molasses after 24 hours. Further fermentation carried out in the fermenter working volume of 3.5 liters, with the condition of temperature 550C, pH 8, aeration 1 vvm, agitation 250 rpm, the highest spesific enzyme of activity of 51,62 ± 0,16 U/mg after 24 hours. Partial purification of xylanase enzyme fermentation is done with the results of microfiltration, ultrafiltration, ammonium sulfate (0-80%) and dialysis. There is an increase in the purity of the enzyme at each stage of purification, the highest purity on dialysis 3.23 times of crude enzymes.Kulit buah pisang kapendis dapat digunakan sebagai pengganti xilan yang harganya mahal, sementara molases selain sebagai sumber karbon serta nitrogen, mineral dan nutrisi dibutuhkan untuk pertumbuhan mikroba yang dapat menghasilkan enzim. Xilanase yang dihasilkan dari Bacillus stearothermopillus DSM 22, menggunakan media kulit pisang kapendis dengan penambahan molase 1%, 2%, dan 3%. Fermentasi dilakukan dalam shaker inkubator pada temperatur 550C, pH awal 8, dan agitasi 250 rpm. Hasilnya menunjukkan aktivitas enzim tertinggi 4,14 ± 0,16 U/mL min., pada penambahan 2% molases setelah 24 jam. Selanjutnya fermentasi dilakukan di dalam fermentor, volume kerja dari 3,5 liter, dengan kondisi temperatur 550C, pH 8, aeration 1 vvm, agitasi 250 rpm, aktivitas spesifik tertinggi 51,62 ± 0,16 U/mg setelah 24 jam. Pemurnian parsial fermentasi enzim xilanase dilakukan dengan hasil mikrofiltrasi, ultrafiltrasi, amonium sulfat (0-80%) dan dialisis. Ada peningkatan kemurnian enzim pada setiap tahap pemurnian, kemurnian tertinggi pada dialisis 3,23 kali dari enzim kasar.Keywords: Xylanase, B. stearothermophillus DSM 22, Cavendish banana peel, molasses, enzyme activity

scholarly journals Enhanced enzymatic activity from phosphotriesterase trimer gold nanoparticle bioconjugates for pesticide detection

The Analyst ◽  
2017 ◽  
Vol 142 (17) ◽  
pp. 3261-3271 ◽  
Author(s):  
John A. Hondred ◽  
Joyce C. Breger ◽  
Nate T. Garland ◽  
Eunkeu Oh ◽  
Kimihiro Susumu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Enzymatic Activity ◽  
Gold Nanoparticle ◽  
Pesticide Detection

A significant enzymatic enhancement of phosphotriesterase has been demonstrated when immobilized on various sized gold nanoparticles.

scholarly journals GENETIC EVIDENCE FOR INTERACTION BETWEEN NONHOMOLOGOUS PROTEINS IN YEAST AND A CASE OF SUPPRESSION AT THE HIS1 LOCUS

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 327-339 ◽  
Author(s):  
Richard Snow
Keyword(s):  
Enzyme Activity ◽  
Low Temperature ◽  
Enzymatic Activity ◽  
Temperature Effect ◽  
Conformational Change ◽  
Minimal Medium ◽  
Genetic Evidence ◽  
Structural Genes ◽  
Wild Type ◽  
Is Strain

ABSTRACT The HIS1 and THR4 loci are the structural genes for phosphoribosyl-ATP pyrophosphorylase and threonine synthetase, respectively. The allele his1-IS has no enzyme activity at 30", but does have activity at 15" provided the cell contains the wild-type THR4 allele or a suppressing allele at another locus, designated SUP(his1-1S). Under these conditions, cells with the hisl-IS mutation are capable of growth on minimal medium at 15". Three kinds of reversions of a hisl-IS thr4 sup(his1-IS) strain to histidine prototrophy have been obtained: (1) his1-IS locus reversions to HIS1 that restore growth without added histidine at 30", (2)  thr4 reversions to THR4 that simultaneously eliminate the requirement for threonine and restore the low-temperature effect on the his1-IS allele, and (3)mutations from sup to SUP. The SUP allele is not an ochre suppressor, and it is not linked to either HISI, THR4 or a centromere. It may represent a missense suppressor. I t is proposed that the effect ofTHR4 is caused by aggregation of the wild-type threonine synthetase with defective his1-IS monomers, causing a favorable conformational change in the histidine protein that restores limited enzymatic activity. This can be regarded as a case of complementation between nonhomologous proteins.

Self-assembled nano-aggregates of fluorinases demonstrate enhanced enzymatic activity, thermostability and reusability

2020 ◽  
Vol 8 (2) ◽  
pp. 648-656
Author(s):  
Chunhao Tu ◽  
Jin Zhou ◽  
Lei Peng ◽  
Shuli Man ◽  
Long Ma
Keyword(s):  
Aqueous Solution ◽  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Self Assembling ◽  
Self Assembled

Three SAP (self-assembling peptide)-tagged fluorinases (FLAs) are successfully prepared. All three SAP-tagged FLAs bear enzymatic activity and they form nano-sized particles in aqueous solution. One of them displays improved enzyme activity, thermostability and reusability.

scholarly journals G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 247-251 ◽  
Author(s):  
GJ Johnson ◽  
ME Kaplan ◽  
E Beutler
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Alternative Mechanism ◽  
Ph Optimum ◽  
Intracellular Enzyme ◽  
Chronic Hemolysis ◽  
Increased Sensitivity ◽  
Normal Sensitivity ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Heat Instability

Abstract The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G- 6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

scholarly journals Enzymatic activity measured by microcalorimetry in soil amended with organic residues

2011 ◽  
Vol 35 (4) ◽  
pp. 1167-1178 ◽  
Author(s):  
Karina Cenciani ◽  
Sueli dos Santos Freitas ◽  
Silvana Auxiliadora Missola Critter ◽  
Claudio Airoldi
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Thermal Effect ◽  
Soil Samples ◽  
Cattle Manure ◽  
Control Treatment ◽  
Municipal Sewage Sludge ◽  
Organic Residues ◽  
Earthworm Casts ◽  
Commercial Enzymes

Enzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox) amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p < 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed a variety of time peaks. These values probably oscillated due to soil physical-chemical factors affecting the enzyme activity on the residues.

scholarly journals Enzyme Characteristics of β-d-Galactosidase- and β-d-Glucuronidase-Positive Bacteria and Their Interference in Rapid Methods for Detection of Waterborne Coliforms andEscherichia coli

1998 ◽  
Vol 64 (3) ◽  
pp. 1018-1023 ◽  
Author(s):  
I. Tryland ◽  
L. Fiksdal
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Environmental Water ◽  
Coliform Bacteria ◽  
Galactosidase Activity ◽  
Fluorogenic Substrates ◽  
Rapid Methods ◽  
E Coli ◽  
Aerococcus Viridans

ABSTRACT Bacteria which were β-d-galactosidase and β-d-glucuronidase positive or expressed only one of these enzymes were isolated from environmental water samples. The enzymatic activity of these bacteria was measured in 25-min assays by using the fluorogenic substrates 4-methylumbelliferyl-β-d-galactoside and 4-methylumbelliferyl-β-d-glucuronide. The enzyme activity, enzyme induction, and enzyme temperature characteristics of target and nontarget bacteria in assays aimed at detecting coliform bacteria and Escherichia coli were investigated. The potential interference of false-positive bacteria was evaluated. Several of the β-d-galactosidase-positive nontarget bacteria but none of the β-d-glucuronidase-positive nontarget bacteria contained unstable enzyme at 44.5°C. The activity of target bacteria was highly inducible. Nontarget bacteria were induced much less or were not induced by the inducers used. The results revealed large variations in the enzyme levels of different β-d-galactosidase- and β-d-glucuronidase-positive bacteria. The induced and noninduced β-d-glucuronidase activities ofBacillus spp. and Aerococcus viridans were approximately the same as the activities of induced E. coli. Except for some isolates identified asAeromonas spp., all of the induced and noninduced β-d-galactosidase-positive, noncoliform isolates exhibited at least 2 log units less mean β-d-galactosidase activity than induced E. coli. The noncoliform bacteria must be present in correspondingly higher concentrations than those of target bacteria to interfere in the rapid assay for detection of coliform bacteria.

Preparation of a phospholipase C-antihuman IgG conjugate, and inhibition of its enzymatic activity by human IgG.

1977 ◽  
Vol 23 (8) ◽  
pp. 1386-1388 ◽  
Author(s):  
R Wei ◽  
S Riebe
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Phospholipase C ◽  
Erythrocyte Membranes ◽  
Human Igg

Abstract We labeled IgG with phospholipase C, using 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide. Enzymaticactivity of the resulting conjugate was inhibited when it was complexed with human IgG, but rabbit or goat IgG was not effective in suppressing the enzyme activity. Normal erythrocytes were used as substrate for the enzyme, enzymatic activity being assessed by measuring the release of hemoglobin. The substrates for phospholipase C are phospholipids, which are major components of the erythrocyte membranes. Hence, the phospholipids in the membranes are viewed as being "immobilized." Perhpas such immobilization of substrate may be a requisite to the inhibition phenomenon.

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