scholarly journals Study of the thermal stability and enzymatic activity of an immobilised enzymatic system for the bilirubin oxidation

Biomaterials ◽  
1999 ◽  
Vol 20 (8) ◽  
pp. 757-763 ◽  
Author(s):  
M Vidal
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Enzymatic System

scholarly journals ENHANCED ENZYMATIC ACTIVITY OF STREPTOMYCES GRISEOPLANUS L-ASPARGINASE VIA ITS INCORPORATION IN AN OIL-BASED NANOCARRIER

2020 ◽  
pp. 203-210
Author(s):  
ABEER A. EL-HADI ◽  
HANAN MOSTAFA AHMED ◽  
RANIA A. ZAKI ◽  
AMIRA MOHAMED MOHSEN
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Enzymatic Activity ◽  
Specific Activity ◽  
Residual Activity ◽  
Tween 80 ◽  
Biochemical Properties ◽  
Lymphocytic Leukemia ◽  
Tween 20 ◽  
Ph Range

Objective: L-asparaginase (L-asp) is a vital enzyme used as a therapeutic agent in combination with other drugs in the treatment of acute lymphoma, melanosarcoma and lymphocytic leukemia. Immobilization of enzymes through loading on nanoemulsion (NE) results in some advantages such as enhancing their stability and increasing their resistance to proteases. Aim of the present study is to formulate L-asp loaded nanoemulsion to enhance its efficiency and thermal stability. Methods: Nanoemulsion loaded with L-asp crude extract (specific activity 13.23U/mg protein) was prepared employing oleic acid as oil, tween 20/tween 80 as surfactants and propylene glycol (PG) as co-surfactant. L-asp loaded NE underwent several thermodynamic stability studies and the optimized formulae were further examined for their biochemical properties and thermal stability. Results The developed formulations were spherical in shape and their sizes were in the nanometric dimensions with negatively charged zeta potential values. Upon comparing the enzyme activity of L-asp loaded NE employing tween 20 (F1) or tween80 (F4) at different concentrations, the results revealed that F4 NE showed higher enzymatic activity [323 U/ml] compared to F1 NE [197 U/ml] at the same concentration. The nanosized immobilized L-asp was more stable in the pH range from 8 to 8.5 as compared to free L-asp. The immobilized enzyme preserved about 59.11% of its residual activity at 50 °C; while free L-asp preserved about 33.84%. Conclusion: In the view of these results, NE composed of oleic acid, tween 80 and PG represents a promising dosage form for enhancing the activity and stability of Streptomyces griseoplanus L-asp.

scholarly journals The calcium-binding site of human glutamate carboxypeptidase II is critical for dimerization, thermal stability, and enzymatic activity

2018 ◽  
Vol 27 (9) ◽  
pp. 1575-1584 ◽  
Author(s):  
Jakub Ptacek ◽  
Jana Nedvedova ◽  
Michal Navratil ◽  
Barbora Havlinova ◽  
Jan Konvalinka ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Binding Site ◽  
Calcium Binding ◽  
Calcium Binding Site ◽  
Glutamate Carboxypeptidase Ii ◽  
Glutamate Carboxypeptidase

IODIDE-PEROXIDASE ACTIVITY IN HUMAN THYROID. I. STUDIES ON NON-TOXIC NODULAR GOITRE

1969 ◽  
Vol 62 (2) ◽  
pp. 193-198 ◽  
Author(s):  
H. Niepomniszcze ◽  
N. Altschuler ◽  
M. H. Korob ◽  
O. J. Degrossi
Keyword(s):  
Enzymatic Activity ◽  
Peroxidase Activity ◽  
Histological Diagnosis ◽  
Human Thyroid ◽  
Enzymatic System ◽  
Iodide Uptake ◽  
Nodular Goitre ◽  
Nodular Tissue ◽  
Toxic Nodular Goitre

ABSTRACT Eighteen nodules from thirteen patients with non-toxic nodular goitre were studied. The nodules were classified, according to the 131I scintiscanner, into »cold« and »warm« types. The histological diagnosis of all the glands was multinodular colloid goitre. An enzymatic system with iodide-peroxidase activity was prepared from nodular tissue obtained by surgical thyroidectomy. The enzymatic activity was determined by spectrophotometry at 287.5 nm by measuring the formation of triiodide ion. The group of »cold« nodules showed an average of 333 units of enzymatic activity and the »warm« nodules 940 units. The significance of the correlation between the capacity for iodide-uptake, the iodide-peroxidase activity and the involution of the metabolic steps in the nodular goitre is discussed.

Effect of compatible and noncompatible osmolytes on the enzymatic activity and thermal stability of bovine liver catalase

2013 ◽  
Vol 31 (12) ◽  
pp. 1440-1454 ◽  
Author(s):  
H. Sepasi Tehrani ◽  
A.A. Moosavi-Movahedi ◽  
H. Ghourchian ◽  
F. Ahmad ◽  
A. Kiany ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Bovine Liver ◽  
Bovine Liver Catalase ◽  
Thermal Stability Of

scholarly journals Enhancing Enzymatic Properties of Endoglucanase I Enzyme from Trichoderma Reesei via Swapping from Cellobiohydrolase I Enzyme

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Aslı Yenenler ◽  
Hasan Kurt ◽  
Osman Sezerman
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Trichoderma Reesei ◽  
Metal Ion ◽  
Structural Integrity ◽  
Green Energy ◽  
Cellobiohydrolase I ◽  
Endoglucanase I ◽  
The Difference ◽  
Spectroscopy Studies

Utilizing plant-based materials as a biofuel source is an increasingly popular attempt to redesign the global energy cycle. This endeavour underlines the potential of cellulase enzymes for green energy production and requires the structural and functional engineering of natural enzymes to enhance their utilization. In this work, we aimed to engineer enzymatic and functional properties of Endoglucanase I (EGI) by swapping the Ala43-Gly83 region of Cellobiohydrolase I (CBHI) from Trichoderma reesei. Herein, we report the enhanced enzymatic activity and improved thermal stability of the engineered enzyme, called EGI_swapped, compared to EGI. The difference in the enzymatic activity profile of EGI_swapped and the EGI enzymes became more pronounced upon increasing metal-ion concentrations in the reaction media. Notably, the engineered enzyme retained a considerable level of enzymatic activity after thermal incubation for 90 min at 70 °C while EGI completely lost its enzymatic activity. Circular Dichroism spectroscopy studies revealed distinctive conformational and thermal susceptibility differences between EGI_swapped and EGI enzymes, confirming the improved structural integrity of the swapped enzyme. This study highlights the importance of swapping the metal-ion coordination region in the engineering of EGI enzyme for enhanced structural and thermal stability.

scholarly journals The Thermal Stability of theFusarium solani pisiCutinase as a Function of pH

2001 ◽  
Vol 1 (2) ◽  
pp. 62-69 ◽  
Author(s):  
Steffen B. Petersen ◽  
Peter Fojan ◽  
Evamaria I. Petersen ◽  
Maria Teresa Neves Petersen
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Fusarium Solani ◽  
Ph Variation ◽  
Electrostatic Contribution ◽  
Molecular Interpretation ◽  
Ph Range ◽  
Thermal Stability Of

We have investigated the thermal stability of theFusarium solani pisicutinase as a function of pH, in the range from pH 2–12. Its highest enzymatic activity coincides with the pH-range at which it displays its highest thermal stability. The unfolding of the enzyme as a function of pH was investigated by microcalorimetry. The ratio between the calorimetric enthalpy (ΔHcal) and the van′t Hoff enthalpy (ΔHv) obtained, is far from unity, indicating that cutinase does not exhibit a simple two state unfolding behaviour. The role of pH on the electrostatic contribution to the thermal stability was assessed using TITRA. We propose a molecular interpretation for the pH-variation in enzymatic activity.

scholarly journals Immobilization of lignin peroxidase from Alcaligenes aquatilis and its application in dye decolorization

2020 ◽  
Vol 9 (2) ◽  
pp. 1058-1063
Keyword(s):  
Thermal Stability ◽  
Enzymatic Activity ◽  
Lignin Peroxidase ◽  
Storage Stability ◽  
Residual Activity ◽  
Dye Decolorization ◽  
High Thermal Stability ◽  
Cross Linking ◽  
Cross Linker ◽  
Ca Alginate

Purefied lignin peroxidase produced from Alcaligenes aquatilis DB8 was immobilized by entrapment on Ca-alginate and chitosan by adsorption and cross linker. Immobilization yields of entrapment, adsorption and cross linking methods were 79.6%, 31.4% and 91.2%, respectively. The thermostability of immobilized LiP by entrapment, adsorption and crosslinking retained residual activity of 68%, 63% and 85%, respectively after 180 min at 50 °C. While the residual activity of free enzyme was decreased to almost half after 180 min. Lignin peroxidase immobilized by crosslinking showed high thermal stability, more than 70% of the enzymatic activity remained after 240 min. Also, immobilized lignin peroxidase by crosslinking showed better storage stability about 55% at 30 days. The application of immobilized lignin peroxidase in a packed bead bioreactor enhanced decolorization of malachite green at 20 mg/l, and the percent of decolorization was 97% at 4 h.

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