A Novel Reversible pH-Triggered Release Immobilized Enzyme System

Gai, Lili; Wu, Daocheng

doi:10.1007/s12010-008-8373-2

Cited by 11 publications

(6 citation statements)

References 28 publications

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“…In contrast, trypsin binds readily to positively charged APTAC microgels at the same conditions, whereas at pH 3, the situation is reversed (Supporting Information, Figure S1). A similar behavior has previously been reported by Gai and Wu, who found trypsin uptake in poly(acrylic acid/methylene-bisacryl-amide) microspheres at pH 4 and pH-triggered release at pH 8 . Given that the isoelectric point of trypsin is about 10.8, this pH and microgel charge behavior is unexpected.…”

Section: Resultssupporting

confidence: 87%

“…A similar behavior has previously been reported by Gai and Wu, who found trypsin uptake in poly(acrylic acid/methylene-bisacryl-amide) microspheres at pH 4 and pH-triggered release at pH 8. 39 Given that the isoelectric point of trypsin is about 10.8, 40 this pH and microgel charge behavior is unexpected. As shown in Supplementary Figure S2, charge distribution is relatively even over the protein surface, and hence one would not expect electrostatic interactions to favor trypsin binding to acrylic acid based microgels at low, but not high, pH or to cationic APTAC microgels but not to anionic acrylic acid based ones.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Factors Affecting Enzymatic Degradation of Microgel-Bound Peptides

2013

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Proteolytic degradation and release of microgel-bound peptides was investigated for trypsin, poly(acrylic acid-co-acrylamide) microgels (70-90 μm in diameter), and oppositely charged polylysine, using a method combination of confocal microscopy and micromanipulator-assisted light microscopy. Results show that trypsin-induced release of polylysine increased with increasing trypsin concentration, decreasing microgel charge density and decreasing peptide molecular weight. While the microgel offered good protection against enzymatic degradation at high microgel charge density, it was also observed that the cationic peptide enabled trypsin to bind throughout the peptide-loaded microgels, even when it did not bind to the peptide-void ones. With the exception of highly charged microgels, proteolytic degradation throughout the peptide-loaded microgel resulted in the generation of short and non-adsorbing peptide stretches, giving rise to the concentration and peptide length dependence observed. A simple random scission model was able to qualitatively capture these experimental findings. Collectively, the results demonstrate that microgel charge density, peptide molecular weight, and enzyme concentration greatly influence degradation/release of microgel-bound peptides and need to be considered in the use of microgels, e.g., as carriers for protein and peptide drugs.

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Section: Resultssupporting

confidence: 87%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Factors Affecting Enzymatic Degradation of Microgel-Bound Peptides

2013

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“…It can provide increased resistance for the immobilized enzyme to the changes in conditions such as pH value or temperature [1]–[5]. Compared with free enzyme systems, immobilized enzymes offer the advantages of having batch or continuous processes operations, rapid termination of reactions, controlled product formation, ease of removal from the reaction mixture, and adaptability to various engineering designs [6]. Thus, enzyme immobilization has been widely used in analysis [7], medicine [8], food [9], chemical industry [10], [11] and biotechnology [12], [13] areas.…”

Section: Introductionmentioning

confidence: 99%

Temperature-Triggered Enzyme Immobilization and Release Based on Cross-Linked Gelatin Nanoparticles

Gan

Zhang

2012

PLoS ONE

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A glucoamylase-immobilized system based on cross-linked gelatin nanoparticles (CLGNs) was prepared by coacervation method. This system exhibited characteristics of temperature-triggered phase transition, which could be used for enzyme immobilization and release. Their morphology and size distribution were examined by transmission electron microscopy and dynamic light scattering particle size analyzer. Their temperature-triggered glucoamylase immobilization and release features were also further investigated under different temperatures. Results showed that the CLGNs were regularly spherical with diameters of 155±5 nm. The loading efficiencies of glucoamylase immobilized by entrapment and adsorption methods were 59.9% and 24.7%, respectively. The immobilized enzyme was released when the system temperature was above 40°C and performed high activity similar to free enzyme due to the optimum temperature range for glucoamylase. On the other hand, there was no enzyme release that could be found when the system temperature was below 40°C. The efficiency of temperature-triggered release was as high as 99.3% for adsorption method, while the release of enzyme from the entrapment method was not detected. These results indicate that CLGNs are promising matrix for temperature-triggered glucoamylase immobilization and release by adsorption immobilization method.

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“…The hydrogel can response to these changes by bending, degrading, swelling, shrinking, color changing, ionization and so on [18,19]. Therefore, these materials are smart and because of these natural properties and their ability to respond to their milieu, they have been extensively exploited in many field e.g., as tissue scaffold for cell growth [20], dressing for would healing [21][22][23], enzyme immobilization [24][25][26], controlled drug delivery [27], gene therapy [28], biosensor [29], and separation and purification [14,30].…”

Section: Introductionmentioning

confidence: 99%