| 1. |
- Franco, Telma Teixeira, et al.
(author)
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Single-step partitioning in aqueous two-phase systems
- 2000
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In: Aqueous Two-Phase Systems – Methods and Protocols. - New Jersey : Humana Press. - 9780896035416 - 9781617370670 - 9781592590285 ; , s. 47-54
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Book chapter (peer-reviewed)abstract
- Partitioning in aqueous two-phase system (ATPS) provides a rapid and gentle means of separation of soluble as well as particulate biomaterials, e.g. proteins, nucleic acids, cells, viruses, organelles, and membranes. Partitioning between the two phases is a complex phenomenon, guided mainly by the interaction of the partitioned substance and the phase components, e.g., through hydrogen bonds, van der Waals-, hydrophobic-, and electrostatic- interactions, steric-, and conformational effects, etc.
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| 2. |
- Hatti-Kaul, Rajni, et al.
(author)
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Aqueous two-phase systems : A general overview
- 2000
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In: Aqueous Two-Phase Systems : Methods and Protocols - Methods and Protocols. - New Jersey : Humana Press. - 9780896035416 - 9781617370670 - 9781592590285 ; , s. 1-10
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Book chapter (peer-reviewed)abstract
- Phase separation in solutions containing polymer mixtures is a very common phenomenon; in fact, miscibility of the polymer mixtures is an exception. Most hydrophilic polymer pairs are incompatible in aqueous solutions yielding two coexisting phases in equilibrium with each other, with each of the phases containing predominantly water and one of the polymer types. It is worth noting that the association of unlike polymer species into a polymer-rich phase coexisting with a polymer-poor phase, referred to as complex coacervation can also occur. However, it is the former type of phase systems that form the subject of this book.
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| 3. |
- Hatti-Kaul, Rajni, et al.
(author)
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Extractive bioconversion in aqueous two-phase systems
- 2000
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In: Aqueous Two-Phase Systems : Methods and Protocols - Methods and Protocols. - New Jersey : Humana Press. - 9780896035416 - 9781617370670 - 9781592590285 ; , s. 411-417
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Book chapter (peer-reviewed)abstract
- Biotechnological processes are characterized, in general, by low productivity and dilute product streams.
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| 4. |
- Kamihira, Masamichi, et al.
(author)
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Integration of extraction with affinity precipitation
- 2000
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In: Aqueous Two-Phase Systems : Methods and Protocols - Methods and Protocols. - New Jersey : Humana Press. - 9780896035416 - 9781617370670 - 9781592590285 ; , s. 371-379
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Book chapter (peer-reviewed)abstract
- Conventional aqueous two-phase extraction by spontaneous partitioning has often problems with low specificity. The introduction of an affinity ligand into one of the phases has been attempted to enhance the specificity of protein partitioning (1-7; Chapters 29-31). However, this procedure still has some limitations in the effective removal of impurities as well as recovery and reuse of the ligand. During the past decade, another potentially scalable technique, affinity precipitation, has been studied for the isolation of proteins (8-10). The affinity ligand coupled to a reversibly soluble-insoluble polymer is used to specifically bind the protein in a complex mixture. The precipitation step which can be accomplished by a change in any environmental parameter such as pH, temperature, salinity, and so forth, facilitates the separation of the bound ligand and affinity complex from the unbound components. Although cells and cell debris should be removed before use, recovery and reuse of the ligand are relatively easy.
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| 5. |
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| 6. |
- Abouhmad, Adel, et al.
(author)
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Exploring the enzymatic and antibacterial activities of novel mycobacteriophage lysin b enzymes
- 2020
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 21:9
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Journal article (peer-reviewed)abstract
- Mycobacteriophages possess different sets of lytic enzymes for disruption of the complex cell envelope of the mycobacteria host cells and release of the viral progeny. Lysin B (LysB) enzymes are mycolylarabinogalactan esterases that cleave the ester bond between the arabinogalactan and mycolic acids in the mycolylarabinogalactan-peptidoglycan (mAGP) complex in the cell envelope of mycobacteria. In the present study, four LysB enzymes were produced recombinantly and characterized with respect to their enzymatic and antibacterial activities. Examination of the kinetic parameters for the hydrolysis of para-nitrophenyl ester substrates, shows LysB-His6 enzymes to be active against a range of substrates (C4-C16), with a catalytic preference towards p-nitrophenyl laurate (C12). With p-nitrophenyl butyrate as substrate, LysB-His6 enzymes showed highest activity at 37◦C. LysB-His6 enzymes also hydrolyzed different Tween substrates with highest activity against Tween 20 and 80. Metal ions like Ca2+ and Mn2+ enhanced the enzymatic activity of LysB-His6 enzymes, while transition metal ions like Zn2+ and Cu2+ inhibited the enzymatic activity. The mycolylarabinogalactan esterase activity of LysB-His6 enzymes against mAGP complex was confirmed by LC-MS. LysB-His6 enzymes showed marginal antibacterial activity when tested alone against Mycobacterium smegmatis, however a synergetic activity was noticed when combined with outer membrane permealizers. These results confirm that LysB enzymes are lipolytic enzymes with potential application as antimycobacterials.
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| 7. |
- Abouhmad, Adel, et al.
(author)
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Immobilization to Positively Charged Cellulose Nanocrystals Enhances the Antibacterial Activity and Stability of Hen Egg White and T4 Lysozyme
- 2017
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 18:5, s. 1600-1608
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Journal article (peer-reviewed)abstract
- Antibacterial bionanostructures were produced from cellulose nanocrystals (CNC) with immobilized lysozyme from hen egg white (HEW) and T4 bacteriophage, respectively. The nanocrystals were prepared from microcrystalline cellulose by ammonium persulfate oxidation with a yield of 68% and having an average size of 250 nm and low polydispersity index. HEW lysozyme (HEWL) and T4 lysozyme (T4L) were immobilized to CNC by different mechanisms including adsorption and covalent coupling to carbodiimide-activated carboxylate groups and to glutaraldehyde-activated aminated CNC (Am-CNC), respectively. The effect of immobilization on the enzymatic activity (both lytic and hydrolytic) and antibacterial activity of the lysozymes was studied using different methods. Am-CNC-lysozyme conjugates retained the highest lytic activity, 86.3% and 78.3% for HEWL and T4L, respectively. They also showed enhanced bactericidal activity with high potency against Gram-positive as well as Gram-negative bacteria in a relatively shorter time as compared to the free enzymes and resulted in extensive cellular damage, as shown by transmission electron microscopy. The enhanced antibacterial activity was correlated with the increase in zeta potential of Am-CNC-lysozyme conjugates. The immobilized lysozyme preparations further exhibited enhanced storage stability at 4 and 22 °C.
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| 8. |
- Adlercreutz, Patrick, et al.
(author)
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Synthesis of Surfactants Using Enzymes
- 2010
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In: Surfactants from Renewable Resources. - Chichester, UK : John Wiley & Sons, Ltd. - 9780470760413 - 9780470686607 ; , s. 143-165
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Book chapter (peer-reviewed)
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| 9. |
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| 10. |
- Alkhalili, Rawana N., et al.
(author)
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Antimicrobial protein candidates from the thermophilic Geobacillus sp. Strain ZGt-1 : Production, proteomics, and bioinformatics analysis
- 2016
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 17:8
-
Journal article (peer-reviewed)abstract
- A thermophilic bacterial strain, Geobacillus sp. ZGt-1, isolated from Zara hot spring in Jordan, was capable of inhibiting the growth of the thermophilic G. stearothermophilus and the mesophilic Bacillus subtilis and Salmonella typhimurium on a solid cultivation medium. Antibacterial activity was not observed when ZGt-1 was cultivated in a liquid medium; however, immobilization of the cells in agar beads that were subjected to sequential batch cultivation in the liquid medium at 60 °C showed increasing antibacterial activity up to 14 cycles. The antibacterial activity was lost on protease treatment of the culture supernatant. Concentration of the protein fraction by ammonium sulphate precipitation followed by denaturing polyacrylamide gel electrophoresis separation and analysis of the gel for antibacterial activity against G. stearothermophilus showed a distinct inhibition zone in 15-20 kDa range, suggesting that the active molecule(s) are resistant to denaturation by SDS. Mass spectrometric analysis of the protein bands around the active region resulted in identification of 22 proteins with molecular weight in the range of interest, three of which were new and are here proposed as potential antimicrobial protein candidates by in silico analysis of their amino acid sequences. Mass spectrometric analysis also indicated the presence of partial sequences of antimicrobial enzymes, amidase, and DD-carboxypeptidase.
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