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Jan A. Delcour – One of the best experts on this subject based on the ideXlab platform.

  • Hydrolysis of amylopectin by amylolytic enzymes: structural analysis of the residual amylopectin population.
    Carbohydrate Research, 2009
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Abstract Amylopectin fine structures were studied following limited hydrolysis of gelatinised waxy maize starch by amylases with a different level of inner chain Attack (LICA). This was done by size exclusion chromatography as well as by debranching the (partially hydrolysed) amylopectin samples and studying the size distributions of the released chains. α-Amylases from Bacillus amyloliquefaciens and Aspergillus oryzae , with a relatively high LICA, drastically altered amylopectin chain length distribution and reduced the amylopectin molecular size (MS) significantly even at a low to moderate degree of hydrolysis (DH). Porcine pancreatic α-amylase (PPA), with a rather low LICA but a high multiple Attack Action on amylose, reduced the amylopectin MS much slower. Following hydrolysis by PPA to a DH of 10% and enzymic debranching of the amylopectin residue, several subpopulations of chains consisting of 2–12 glucose units were detected, indicating a multiple Attack Action on the amylopectin side chains. During the early stages of hydrolysis, the maltogenic Bacillus stearothermophilus α-amylase (BStA) preferentially hydrolysed the exterior chains of amylopectin. However, during the later phases, BStA also hydrolysed inner chains, presumably with a high multiple Attack Action. The present results clearly show that different enzymes can be used for (limited) conversion of amylopectin into structures differing in molecular weight and chain length distributions.

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  • Amylase Action pattern on starch polymers
    Biologia, 2008
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Several decades ago, the first reports on differences in Action pattern between amylases from different sources indicated that the starch polymers are not degraded in a completely random manner. We here give an overview of different Action patterns of amylases on amylose and amylopectin, focusing on the so-called multiple Attack Action of the enzymes. Nowadays, the multiple Attack Action is generally an accepted concept to explain the differences in amylase Action pattern. However, the pancreatic α -amylase remains one of the few enzymes known with a considerable level of multiple Attack Action. Despite some recent studies, the molecular mechanism of the multiple Attack Action is still largely unclear. Probably, the degree to which the active site architecture and binding properties allow both the reorganization (sliding) of the substrate in the active site and the stabilisation of the productive enzyme/substrate complex mainly determine the multiple Attack Action of amylases.

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  • Temperature impacts the multiple Attack Action of amylases
    Biomacromolecules, 2007
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    The Action pattern of several amylases was studied at 35, 50, and 70 °C using potato amylose, a soluble (Red Starch) and insoluble (cross-linked amylose) chromophoric substrate. With potato amylose as substrate, Bacillus stearothermophilus α-amylase (BStA) and porcine pancreatic α-amylase displayed a high degree of multiple Attack (DMA, i.e., the number of bonds broken during the lifetime of an enzyme−substrate complex minus one), the fungal α-amylase from Aspergillus oryzae a low DMA, and the α-amylases from B. licheniformis, Thermoactinomyces vulgaris, B. amyloliquifaciens, and B. subtilis an intermediate DMA. These data are discussed in relation to structural properties of the enzymes. The level of multiple Attack (LMA), based on the relation between the drop in iodine binding of amylose and the increase in total reducing value, proved to be a good alternative for DMA measurements. The LMA of the endo-amylases increased with temperature to a degree depending on the amylase. In contrast, BStA showed a d…

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Annabel Bijttebier – One of the best experts on this subject based on the ideXlab platform.

  • Hydrolysis of amylopectin by amylolytic enzymes: structural analysis of the residual amylopectin population.
    Carbohydrate Research, 2009
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Abstract Amylopectin fine structures were studied following limited hydrolysis of gelatinised waxy maize starch by amylases with a different level of inner chain Attack (LICA). This was done by size exclusion chromatography as well as by debranching the (partially hydrolysed) amylopectin samples and studying the size distributions of the released chains. α-Amylases from Bacillus amyloliquefaciens and Aspergillus oryzae , with a relatively high LICA, drastically altered amylopectin chain length distribution and reduced the amylopectin molecular size (MS) significantly even at a low to moderate degree of hydrolysis (DH). Porcine pancreatic α-amylase (PPA), with a rather low LICA but a high multiple Attack Action on amylose, reduced the amylopectin MS much slower. Following hydrolysis by PPA to a DH of 10% and enzymic debranching of the amylopectin residue, several subpopulations of chains consisting of 2–12 glucose units were detected, indicating a multiple Attack Action on the amylopectin side chains. During the early stages of hydrolysis, the maltogenic Bacillus stearothermophilus α-amylase (BStA) preferentially hydrolysed the exterior chains of amylopectin. However, during the later phases, BStA also hydrolysed inner chains, presumably with a high multiple Attack Action. The present results clearly show that different enzymes can be used for (limited) conversion of amylopectin into structures differing in molecular weight and chain length distributions.

    Free Register to Access Article

  • Amylase Action pattern on starch polymers
    Biologia, 2008
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Several decades ago, the first reports on differences in Action pattern between amylases from different sources indicated that the starch polymers are not degraded in a completely random manner. We here give an overview of different Action patterns of amylases on amylose and amylopectin, focusing on the so-called multiple Attack Action of the enzymes. Nowadays, the multiple Attack Action is generally an accepted concept to explain the differences in amylase Action pattern. However, the pancreatic α -amylase remains one of the few enzymes known with a considerable level of multiple Attack Action. Despite some recent studies, the molecular mechanism of the multiple Attack Action is still largely unclear. Probably, the degree to which the active site architecture and binding properties allow both the reorganization (sliding) of the substrate in the active site and the stabilisation of the productive enzyme/substrate complex mainly determine the multiple Attack Action of amylases.

    Free Register to Access Article

  • Temperature impacts the multiple Attack Action of amylases
    Biomacromolecules, 2007
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    The Action pattern of several amylases was studied at 35, 50, and 70 °C using potato amylose, a soluble (Red Starch) and insoluble (cross-linked amylose) chromophoric substrate. With potato amylose as substrate, Bacillus stearothermophilus α-amylase (BStA) and porcine pancreatic α-amylase displayed a high degree of multiple Attack (DMA, i.e., the number of bonds broken during the lifetime of an enzyme−substrate complex minus one), the fungal α-amylase from Aspergillus oryzae a low DMA, and the α-amylases from B. licheniformis, Thermoactinomyces vulgaris, B. amyloliquifaciens, and B. subtilis an intermediate DMA. These data are discussed in relation to structural properties of the enzymes. The level of multiple Attack (LMA), based on the relation between the drop in iodine binding of amylose and the increase in total reducing value, proved to be a good alternative for DMA measurements. The LMA of the endo-amylases increased with temperature to a degree depending on the amylase. In contrast, BStA showed a d…

    Free Register to Access Article

Hans Goesaert – One of the best experts on this subject based on the ideXlab platform.

  • Hydrolysis of amylopectin by amylolytic enzymes: structural analysis of the residual amylopectin population.
    Carbohydrate Research, 2009
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Abstract Amylopectin fine structures were studied following limited hydrolysis of gelatinised waxy maize starch by amylases with a different level of inner chain Attack (LICA). This was done by size exclusion chromatography as well as by debranching the (partially hydrolysed) amylopectin samples and studying the size distributions of the released chains. α-Amylases from Bacillus amyloliquefaciens and Aspergillus oryzae , with a relatively high LICA, drastically altered amylopectin chain length distribution and reduced the amylopectin molecular size (MS) significantly even at a low to moderate degree of hydrolysis (DH). Porcine pancreatic α-amylase (PPA), with a rather low LICA but a high multiple Attack Action on amylose, reduced the amylopectin MS much slower. Following hydrolysis by PPA to a DH of 10% and enzymic debranching of the amylopectin residue, several subpopulations of chains consisting of 2–12 glucose units were detected, indicating a multiple Attack Action on the amylopectin side chains. During the early stages of hydrolysis, the maltogenic Bacillus stearothermophilus α-amylase (BStA) preferentially hydrolysed the exterior chains of amylopectin. However, during the later phases, BStA also hydrolysed inner chains, presumably with a high multiple Attack Action. The present results clearly show that different enzymes can be used for (limited) conversion of amylopectin into structures differing in molecular weight and chain length distributions.

    Free Register to Access Article

  • Amylase Action pattern on starch polymers
    Biologia, 2008
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    Several decades ago, the first reports on differences in Action pattern between amylases from different sources indicated that the starch polymers are not degraded in a completely random manner. We here give an overview of different Action patterns of amylases on amylose and amylopectin, focusing on the so-called multiple Attack Action of the enzymes. Nowadays, the multiple Attack Action is generally an accepted concept to explain the differences in amylase Action pattern. However, the pancreatic α -amylase remains one of the few enzymes known with a considerable level of multiple Attack Action. Despite some recent studies, the molecular mechanism of the multiple Attack Action is still largely unclear. Probably, the degree to which the active site architecture and binding properties allow both the reorganization (sliding) of the substrate in the active site and the stabilisation of the productive enzyme/substrate complex mainly determine the multiple Attack Action of amylases.

    Free Register to Access Article

  • Temperature impacts the multiple Attack Action of amylases
    Biomacromolecules, 2007
    Co-Authors: Annabel Bijttebier, Hans Goesaert, Jan A. Delcour

    Abstract:

    The Action pattern of several amylases was studied at 35, 50, and 70 °C using potato amylose, a soluble (Red Starch) and insoluble (cross-linked amylose) chromophoric substrate. With potato amylose as substrate, Bacillus stearothermophilus α-amylase (BStA) and porcine pancreatic α-amylase displayed a high degree of multiple Attack (DMA, i.e., the number of bonds broken during the lifetime of an enzyme−substrate complex minus one), the fungal α-amylase from Aspergillus oryzae a low DMA, and the α-amylases from B. licheniformis, Thermoactinomyces vulgaris, B. amyloliquifaciens, and B. subtilis an intermediate DMA. These data are discussed in relation to structural properties of the enzymes. The level of multiple Attack (LMA), based on the relation between the drop in iodine binding of amylose and the increase in total reducing value, proved to be a good alternative for DMA measurements. The LMA of the endo-amylases increased with temperature to a degree depending on the amylase. In contrast, BStA showed a d…

    Free Register to Access Article