Amylose Synthesized in Vitro by Amylosucrase: Morphology, Structure, and Properties
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- 作者：Gabrielle Potocki-Veronese ; Jean-Luc Putaux ; Danielle Dupeyre ; Cé ; cile Albenne ; Magali Remaud-Simé ; on ; Pierre Monsan ; and Alain Buleon
- 刊名：Biomacromolecules
- 出版年：2005
- 出版时间：March 2005
- 年：2005
- 卷：6
- 期：2
- 页码：1000 - 1011
- 全文大小：763K
- 年卷期：v.6,no.2(March 2005)
- ISSN：1526-4602
文摘
The recombinant amylosucrase from Neisseria polysaccharea was used to synthesize in vitro amylose fromsucrose as unique substrate. The morphology and structure of the insoluble residue were shown to dependonly on the initial sucrose concentration (100, 300, or 600 mM), which controlled both the chain length andconcentration at the precipitation stage. The average degree of polymerization (
) in the precipitatedproduct varied from 58 for the lowest initial sucrose concentration (100 mM) to 45 and 35 for higher sucroseconcentrations (300 and 600 mM, respectively). The shorter chains (
35 and 45), produced in high yields(54 and 24 g/L respectively), precipitated as polycrystalline aggregates with exceptional crystallinity, withoutoptimization of the reaction medium for crystallization. The longer chains (
58), produced in loweramount (2.9 g/L), formed networks similar to those observed for amylose gels. All synthesized productsdisplayed a B-type crystal structure. Their melting behavior was also studied, the thermostability beinghigher for the precipitate containing the longer chains. Further thermal treatments were shown to still improvethe crystallinity and yield substrates usable as new standards for the determination of the relative crystallinityof starchy products. The kinetics of chain elongation and aggregation were thoroughly investigated in orderto explain how the action of amylosucrase resulted in such different amylose structures. These resultsemphasize the potientiality of amylosucrase in the design of amylodextrins with controlled morphology,structure, and physicochemical properties.
) in the precipitatedproduct varied from 58 for the lowest initial sucrose concentration (100 mM) to 45 and 35 for higher sucroseconcentrations (300 and 600 mM, respectively). The shorter chains ( 35 and 45), produced in high yields(54 and 24 g/L respectively), precipitated as polycrystalline aggregates with exceptional crystallinity, withoutoptimization of the reaction medium for crystallization. The longer chains ( 58), produced in loweramount (2.9 g/L), formed networks similar to those observed for amylose gels. All synthesized productsdisplayed a B-type crystal structure. Their melting behavior was also studied, the thermostability beinghigher for the precipitate containing the longer chains. Further thermal treatments were shown to still improvethe crystallinity and yield substrates usable as new standards for the determination of the relative crystallinityof starchy products. The kinetics of chain elongation and aggregation were thoroughly investigated in orderto explain how the action of amylosucrase resulted in such different amylose structures. These resultsemphasize the potientiality of amylosucrase in the design of amylodextrins with controlled morphology,structure, and physicochemical properties.