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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 681 (1982), S. 212-219 
    ISSN: 0005-2728
    Keywords: (Mesotaenium caldariorum) ; Chlorophyll orientation ; Dichroism ; Microphotometry ; Photosynthesis
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Substance Abuse 5 (1993), S. 187-193 
    ISSN: 0899-3289
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine , Psychology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 10 (1990), S. 41-48 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Five cellulases were fractionated from a commercial cellulase preparation (CelluclastTM) Two isoenzymes of cellobiohydrolase I (CBHI)(pI = 4.1) could be proved to be real exo-glucanases due to their activity towards MU (=methylumbelliferyl)-lactoside being inhibited by cellobiose (5 mM) and due to production of cellobiose from carboxymethylcellulose (CMC) as the sole final product.Two isoenzymes of CBHII (pI=6.15, 6.0) were shown to act as endo-glucanases because they produced glucose, cellobiose and cellotetraose from CMC and because they were not inhibited by cellobiose when decomposing MU-lactoside. Results confirm recent reports in the literature classifying CBHI and CBHII as exo-type and endo-type cellulases, respectively. Both the CBHI and the CBHII isoenzymes were shown to be active towards CMC and amorphous cellulose.CBHI and CBHII reactions could be differentiated from one another by the velocities of decomposition of CMC: CBHI acts slowly and linearly whereas CBHII acts strongly and exponentially.The fifth of the purified enzymes must be classed as a conventional endoglucanase which exhibits activity towards CMC but fails to be active towards MU-lactoside and amorphous cellulose.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 11 (1991), S. 279-286 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Decompositions of amorphous cellulose induced by cellulases of Trichoderma reesei were evaluated from gradients at zero time of exponential functions which were fitted to nephelometrically measured values of turbidty of incubated solutions of cellulose [turbidity = A × exp (B × t)+ C [A, B, C = constants, t = time]]. Synergistic enhancements of decomposition of amorphous cellulose resulted in the range of 300 p.c. whenever of the two isoenzymes of cellobiohydrolase I of Trichoderma reesei (CBH I, being an exo-glucanase) one was incubated together with one of the isoenzymes of CBH II (being really an endo-glucanase). Accessibility of amorphous cellulose to enzymatic decomposition being calculated from the fitted function by the term (A/(A + C)) × 100 [p.c.] resulted for the CBH I isoenzymes and for the CBH II/1 in the range of 27 to 38 p.c. of the total substrate. Incubations of CBH II/1 in with CBH I/1 and CBH I/2 were followed by increases of accessibility to 85 and 87 p.c., respectively. CBH II/2 by itself caused a substrate accessibility in the range of 80 p.c., which increased to 96 p.c. when it was incubated together with CBH I/1 or CBH I/2. Amorphous cellulose dispersing activity (ACD activity) being evaluated from the fitted function by the term (A + C)/(Ac + Cc) × 100 [p.c.] (Ac + Cc × control turbidity at zero time) was not increased when a CBH I isoenzyme was incubated together with a CBH II isoenzyme. EG I, a convetional endo-glucanase from Tr. reesei proved not to act synergistically in any case when incubated together with one of the CBH isoenzymes. On the contrary, EG I turned out to act antagonistically to CBH II/1 and CBH II/2. Results can be interpreted as an exo-endo-synergism taking place between C1-specific exo- and endo-glucanases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 11 (1991), S. 359-365 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: WHATMAN 1 CHR filter paper manufactured from macerated cotton fibers was shown to be a soft substrate when broken down by purified cellulases of Trichoderma reesei (CELLUCLAST). Destruction of filter-paper disks was induced by CBH I/1, CBH I/2, CBH II/1, CBH II/2, and EG I in a macroscopic assay. Attack on disks by mixtures of these cellulases (CBH I/1 or CBH I/2 mixed with CBH II/1, CBH II/2, or with EGJ) were followed by synergistically enhanced destructions.SCHLEICHER &SCHUELL filter paper No 595 was shown to be a harder substrate of enzymatical decomposition when induced by cellulases of CELLUCLAST. None of the cellulases could induce macroscopic destruction of filter-paper disks when acting in isolation. However, mixtures of isolated exo and endo-glucanases (CBH I/1 or CBH I/2 mixed with CBH II/1, CBH II/2, or EG I) caused powerful destruction of filter-paper disks.SCHLEICHER &SCHUELL filter paper No 595 incubated first with an endo-glucanase (CBH II/1, CBH II/2, EG I) and treated in a secondary incubation with an exo-glucanase (CBH I/1, CBH I/2) were destroyed to a greater extent than with incubations executed in the reverse order. Results confirm the endo exo concept of explaining cellulose decomposition.The filter-paper destruction assay was performed with filter-paper disks prepared with an office punch. Disks were incubated in 1 ml EPPENDORF reaction tubes filled up beforehand with 0.4 or 0.5 ml of enzyme solution. The degree of synergism of cellulases resulted from the assay in the range of 300 to 1 300 p.c.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two isoenzymes of cellobiohydrolase I (CBHI/1 and CBHI/2) of Trichoderma reesei purified from CelluclastTM are shown to cause a new mode of reaction which is exhibited additionally to the known exo-glucanase reaction of CBHI: Dispersion of amorphous cellulose solution is increased by CBHI/1 and CBHI/2 to 49 and 64 p.c., respectively, before decompositions of substrate as induced by the same enzymes become detectable. Amorphous-cellulose dispersing activity of CBHI is reduced by cellobiose which is known to be an inhibitor of CBHI. Amorphous-cellulose dispersing activity was also observed of a CBHII isoenzyme (CBHII/2), an endo-glucanase and complete Celluclast, however, to lesser extents (17, 12, 35 p.c., respectively). Observations with a phase-contrast microscope determined an increase of dispersion of particles of amorphous cellulose induced by cellulases of Celluclast. Decompositions of amorphous cellulose run almost linearly and quite exponentially when induced by CBHI and CBHII, respectively, allowing differentiation between exo-glucanase and endo-glucanase activities of these cellulases.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989), S. 179-190 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The cellulase complex of the fungus Aspergillus niger (strain CBS 554.65 = ATCC 16 888) was fractionated by gel filtration yielding six pronounced peaks. Only proteins from the fraction corresponding to the first peak (96 kDa) showed β-glucosidase activity vs. the substrate 4-nitrophenyl-β-D-glucopyranoside (pNPG). These proteins have been fractionated by chromatofocusing, yielding two β-glucosidases (I and II) which are shown to be homogeneous in isoelectric focusing experiments (pI = 4.6 and 3.8, respectively). Kinetic experiments with pNPG, MU-glucopyranoside and cellobiose revealed that both types of β-glucosidases behave like aryl-β-glucosidases. β-Glucosidase-I acting on pNPG exhibits a split kinetics characterized by high and low substrateconcentration kinetics which are differentiated by different values of V and of Km. In addition, β-glucosidase-II is shown to be an exo-glucohydrolase as deduced from experiments with MU-cellobiopyranoside.Experimental features should be emphasized; usual soft-gel ion-exchange materials did not work in the chromatofocusing separation of the two β-glucosidases, in contrast to the 10μ-Si 500 = DEAE exchange material (Serva) typically used in HPLC-experiments. Furthermore, protein content determinations based on different procedures yielded widely differing values.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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