Amylose enzymatic polymerization with

By studying the polydispersities of amyloses obtained by enzymatic polymerization with potato phosphorylase from maltooligosaccharides of various lengths, Pfannemiiller and Burchard were able to show that the reaction mechanism of the polymerization with maltotriose as primer varies from its higher homologs [45]. While the amyloses built by polymerization from maltotetraose or higher showed a Poisson distribution [46] that can be expected from a polymerization... 

Amylose Hybrids with Short Alkyl Chains Pfannemuller et al. showed that it is possible to obtain carbohydrate-containing amphiphiles with various alkyl chains via amide bond formation. For this, maltooligosaccharides were oxidized to the corresponding aldonic acid lactones which could subsequently be coupled to alkylamines [52-60]. Such sugar-based surfactants are important industrial products finding their applications in cosmetics, medical applications etc. [61-63]. The authors were also able to extend the attached maltooligosaccharides with enzymatic polymerization with potato phosphorylase which resulted in products with very interesting solution properties [64, 65]. 

An interesting procedure has been proposed for the synthesis of amylose-b-PS block copolymers through the combination of anionic and enzymatic polymerization [131]. PS end-functionalized with primary amine or dimethylsilyl, -SiMe2H groups were prepared by anionic polymerization techniques, as shown in Scheme 56. The PS chains represented by the curved lines in Scheme 56 were further functionalized with maltoheptaose oligomer either through reductive amination (Scheme 57) or hydrosilyla-tion reactions (Scheme 58). In the first case sodium cyanoborohydride was used to couple the saccharide moiety with the PS primary amine group. 

The glycogen phosphorolysis of phosphorylase can be reverted, which makes it possible to enzymatically polymerize amylose as well as hybrid structures with amylose as outlined in the following section. 

Enzymatic Polymerization of Amylose with Glycogen Phosphorylase... 

The first surface-initiated enzymatic polymerization reported was the synthesis of amylose brushes on planar and spherical surfaces [145]. For this, silica or silicone surfaces were modified with self-assembled monolayers of (3 amino-propyl)trimethoxysilane or chlorodimethylsilane, respectively. To these functionalities, oligosaccharides were added via (a) reductive amidation of the oligosaccharides to surface-bound amines, (b) conversion of the oiigosaccharide to the according aldonic acid lactone and reaction with surface bound amines, and (c) incorporation... 

In all cases, the authors could successfully elongate the attached oligosaccharide structures using enzymatic polymerization, the product being comb-type block copolymers with amylose. 

V. V. Braunmuhl, R. Stadler, Macromol. Symp. 1996, 103, 141-148. Polydimethylsrloxanes with amylose side chains by enzymatic polymerization ... 

The strict primer dependence of the glycogen phosphorylases makes them ideal candidates for the synthesis of hybrid structures of amylose with non-natural materials (e.g., inorganic particles and surfaces, synthetic polymers). For this, a primer functionality (maltooligosaccharide) can be coupled to a synthetic structure and subsequently elongated by enzymatic polymerization resulting in amylose blocks. 

Enzymatic polymerization of amylose with glycogen phosphorylase... 

Another tjqie of comb like amylose hybrids synthesized via enzymatic grafting with phosphorylase is based on polysiloxane backbones. To achieve these structures double bonds were incorporated to the reducing end of oligosaccharides which were then attached to poIy(dimethylsiloxane-co-methylsiloxane) copolymers via hydrosililation or to silane monomers which were subsequently polymerized to polysiloxanes . Various mono-, d>-, tri and oligosaccharides were attached to siloxane backbones and their solution properties were studied with viscosimetry and static and dynamic light... 

Various linear block copolymers of the AB, ABA and ABC type with enzymatically polymerized amylose blocks were reported. Ziegast and Pfannemuller converted the hydroxyl end groups of poly(ethylene oxide) into amino groups via tosylation and further reaction with 2-aminoalkylthiolate. To the resulting mono- and di-amino functionalized poly(ethylene oxide) maltooligosaccharide lactones were attached and subsequently elongated to amylose via enzymatic polymerization. Pfannemuller et al. performed a very detailed study on the solution properties of the synthesized A-B-A triblock... 

The results reviewed above clearly show that the combination of enzymatically polymerized amylose with surfaces of inorganic materials and... 

An alternative strategy toward the formation of such inclusion complexes, reported by Kadokawa et al., is to use the enzymatic polymerization of glucose on a template polymer, where phosphorylase catalyzes a polymerization reaction of a-D-glucose 1-phosphate monomer along the template polymer [poly(tetrahydrofuran)] in a twisting manner [17]. The same inclusion complex was not formed upon just mixing natural amylose with polymer [poly(tetrahydrofuran)], probably due to the rigid conformation of natural amylose. 

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