| 1. |
- Henriksson, Gunnar, et al.
(författare)
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Endoglucanase 28 (Cel12A), a new Phanerochaete chrysosporium cellulase.
- 1999
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Ingår i: European Journal of Biochemistry. - 0014-2956 .- 1432-1033. ; 259:1-2, s. 88-95
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Tidskriftsartikel (refereegranskat)abstract
- A 28-kDa endoglucanase was isolated from the culture filtrate of Phanerochaete chrysosporium strain K3 and named EG 28. It degrades carboxymethylated cellulose and amorphous cellulose, and to a lesser degree xylan and mannan but not microcrystalline cellulose (Avicel). EG 28 is unusual among cellulases from aerobic fungi, in that it appears to lack a cellulose-binding domain and does not bind to crystalline cellulose. The enzyme is efficient at releasing short fibres from filter paper and mechanical pulp, and acts synergistically with cellobiohydrolases. Its mode of degrading filter paper appears to be different to that of endoglucanase I from Trichoderma reesei. Furthermore, EG 28 releases colour from stained cellulose beads faster than any other enzyme tested. Peptide mapping suggests that it is not a fragment of another known endoglucanases from P. chrysosporium and peptide sequences indicate that it belongs to family 12 of the glycosyl hydrolases. EG 28 is glycosylated. The biological function of the enzyme is discussed, and it is hypothesized that it is homologous to EG III in Trichoderma reesei and the role of the enzyme is to make the cellulose in wood more accessible to other cellulases.
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| 2. |
- Henriksson, Chris, 1938-, et al.
(författare)
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Evaluation of four outpatient educational programmes for patients with longstanding fibromyalgia
- 2004
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Ingår i: Journal of Rehabilitation Medicine. - : Medical Journals Sweden AB. - 1650-1977 .- 1651-2081. ; 36:5, s. 211-219
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Four programmes based on educational and cognitive principles but with a variation in total length and number of staff/patient contact hours were compared in order to gain further insight into the importance of the format of the programme for the final outcome.DESIGN: A prospective non-randomized intervention study with 191 persons with fibromyalgia. Data were collected before, after and at 1-year follow-up. Participants served as their own controls. Results within and between the programmes were calculated.METHODS: Clinical investigations before and after intervention. Questionnaires were answered before, after and at 1-year follow-up.RESULTS: Most instruments showed no significant improvements after the programme. However, some improvements were found in important variables such as attitudes, self-efficacy, vitality and "days feeling well". Results were unchanged at the 1-year follow-up and 16 persons had started working. Seven had ceased working. Participants reported frequent use of coping strategies in everyday life. No major differences could be found between the programmes. Conclusions: More comprehensive programmes did not produce better results at group level. Also short and less costly interventions based on educational and cognitive principles were valuable for persons with longstanding fibromyalgia. More attention must be given to evaluating the clinical effect of programmes.
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| 3. |
- Henriksson, Gunnar, et al.
(författare)
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A critical review of cellobiose dehydrogenases
- 2000
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Ingår i: Journal of Biotechnology. - : ELSEVIER SCIENCE BV. - 0168-1656 .- 1873-4863. ; 78:2, s. 93-113
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Forskningsöversikt (refereegranskat)abstract
- Cellobiose dehydrogenase (CDH) is an extracellular enzyme produced by various wood-degrading fungi. It oxidizes soluble cellodextrins, mannodextrins and lactose efficiently to their corresponding lactones by a ping-pong mechanism using a wide spectrum of electron accepters including quinones, phenoxyradicals, Fe3+, Cu2+ and tiiodide ion. Monosaccharides, maltose and molecular oxygen are:poop substrates. CDH that adsorbs strongly and specifically to cellulose carries two prosthetic groups; namely, an FAD and a heme in two different domains that can be separated after limited proteolysis. The FAD-containing fragment carries all known catalytic and cellulose binding properties. One-electron accepters, like ferricyanide, cytochrome c and phenoxy radicals, are, however, reduced more slowly by the FAD-fragment than by the intact enzyme, suggesting that the function of the heme group is to facilitate one-electron transfer. Non-heme forms of CDH have been found in the culture filtrate of some fungi (probably due to the action of fungal proteases) and were for a long time believed to represent a separate enzyme (cellobiose:quinone oxidoreductase, CBQ). The amino acid sequence of CDH has been determined and no significant homology with other proteins was detected for the heme domain. The FAD-domain sequence belongs to the GMC oxidoreductase family that includes, among others, Aspergillus niger glucose oxidase. The homology is most distinct in regions that correspond to the FAD-binding domain in glucose oxidase. A cellulose-binding domain of the fungal type is present in CDH from Myceliophtore thermophila (Sporotrichum thermophile), but in others an internal sequence rich in aromatic amino acid residues has been suggested to be responsible for the cellulose binding. The biological function of CDH is not fully understood, but recent results support a hydroxyl radical-generating mechanism whereby the radical can degrade and modify cellulose, hemicellulose and lignin. CDH has found technical use in highly selective amperometric biosensors and several other applications have been suggested.
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| 4. |
- Henriksson, Gunnar, 1965-, et al.
(författare)
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Monocomponent endoglucanases : an excellent tool in wood chemistry and pulp processing
- 2005
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Ingår i: 13th ISWFPC (International Symposium on Wood, Fibre and Pulping Chemistry), Auckland, New Zealand, 16-19 May 2005: Proceedings. ; , s. 503-508
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Konferensbidrag (refereegranskat)abstract
- Highly pure cellulases of endoglucanase type produced by genetically modified fungi are commercially available. They are useful tools both for analytical wood chemistry and potentially also as industrial chemicals for novel processes for the pulp and paper industry. Here the functionality of cellulases and some application of endoglucanases are reviewed. The mechanisms behind the effects of the enzyme are discussed.
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| 5. |
- Henriksson, Gunnar, et al.
(författare)
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Substrate specificity of cellobiose dehydrogenase from Phanerochaete chrysosporium
- 1998
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 1383:1, s. 48-54
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Tidskriftsartikel (refereegranskat)abstract
- Substrate structural mapping suggests that the catalytic site of cellobiose dehydrogenase from Phanerochaete chrysosporium forms a narrow cave with two hexose binding subsites, Kinetic data also show that beta-di or oligosaccharides are favored electron donors with respect to both KM and kcat. Surprisingly, thiocellobiose showed an even higher kcat than cellobiose, although the KM value was somewhat higher. The CDH was purified using an updated protocol.
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| 6. |
- Henriksson, Marielle, et al.
(författare)
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An environmentally friendly method for enzyme-assisted preparation of microfibrillated cellulose (MFC) nanofibers
- 2007
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Ingår i: European Polymer Journal. - : Elsevier BV. - 0014-3057 .- 1873-1945. ; 43:8, s. 3434-3441
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Tidskriftsartikel (refereegranskat)abstract
- Microfibrillated cellulose nanofibers (MFC) provide strong reinforcement in polymer nanocomposites. In the present study, cellulosic wood fiber pulps are treated by endoglucanases or acid hydrolysis in combination with mechanical shearing in order to disintegrate MFC from the wood fiber cell wall. After successful disintegration, the MFC nanofibers were studied by atomic force microscopy (AFM). Enzyme-treatment was found to facilitate disintegration, and the MFC nanofibers produced also showed higher average molar mass and larger aspect ratio than nanofibers resulting from acidic pretreatment.
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| 7. |
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| 8. |
- Kjellander, Marcus
(författare)
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Nanoporous Aluminum Oxide – A Promising Support for Modular Enzyme Reactors
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nanoporous alumina is a rather newly characterized material that so far has found limited use in the construction of bioreactors. The material has many advantages compared to conventional immobilization matrices. I have investigated its use in flow-through bioreactors. The rigidity and porous structure of the material makes it an excellent choice for multienzyme reactor construction. The total activity in a reactor is easily controlled by the number of membranes since the porosity makes the material less prone to increase flow system pressure. This bioreactor is suitable for characterization of new enzymes since the amount of immobilized enzyme is standardized and the enzyme may be reused many times.We designed a simple stepwise technique for covalent immobilization on this matrix in a monolayer to minimize mass transfer effects in the reactor function. The kinetic parameters for ten different substrates were investigated for immobilized alcohol oxidase and, as a second step, a two-step reactor was also designed by addition of horseradish peroxidase. This bienzymatic reactor was, in turn, employed for measuring injected alcohol concentrations. The use of the matrix for substrate specificity screening was proven for two new epsilon-class glutathione transferases from Drosophila melanogaster. Immobilized trypsin showed a substantially prolonged lifetime and its potential use as an on-line digestion unit for peptide mass fingerprinting was also demonstrated. Finally, I investigated the immobilization of the model enzyme lactate dehydrogenase by adsorption mediated by metal ion chelation similar to IMAC. Regeneration was here possible multiple times without loss of capacity. In conclusion, immobilization of enzymes on nanoporous alumina is a convenient way to characterize, stabilize and reuse enzymes.
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| 9. |
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| 10. |
- Lawoko, M., et al.
(författare)
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Hemicellulase activity of aerobic fungal cellulases
- 2000
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Ingår i: Holzforschung. - 0018-3830 .- 1437-434X. ; 54:5, s. 497-500
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Tidskriftsartikel (refereegranskat)abstract
- Cellulases isolated from Trichoderma reesei and Phanerochaete chrysosporium were screened for hemi-cellulolytic, pectinolytic and cellulolytic activity using locust bean mannan, birchwood xylan, citrus fruit pectin and carboxymethylated cellulose (CMC) as substrates. The purpose of this work was to choose appropriate enzymes to include in a miniature cellulase system with minimal hemicellulase activity for the preparation of lignin-carbohydrate complexes (LCCs). The endoglucanases showed CMC activity whereas activity towards the substrate was not detected for the CBHs. Xylanase activity was observed for EG I and EG 38 whereas mannanase activity was observed for EG 44. None of the enzymes degraded pectin. The results suggest that CBH I, CBH II, CBH 58, EG II and EG III are good candidates for the effective preparation of LCCs. The possible biological function for the hemicellulolytic activity of cellulases is discussed.
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