Glycogen phosphorylase amylose with

Enzymatic Polymerization of Amylose with Glycogen Phosphorylase... 

The strict primer dependence of the glycogen phosphorylases makes them ideal candidates for the synthesis of hybrid structures of amylose with non-natural materials... 

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... 

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. 

Earlier studies on the properties of phosphorylases isolated from various sources have indicated that their subunits are similar in size with about 100,000 daltons.15-17 The reaction proceeds in a rapid equilibrium random Bi-Bi mechanism as has been shown by kinetic studies with rabbit skeletal muscle phosphorylases a18-20 and b,21,22 rabbit liver enzyme,23 potato tuber enzyme,24 and the enzyme from E. coli.25) In contrast, the substrate specificities for various glucans differ considerably depending on the enzyme sources. The rabbit muscle enzyme has high affinity for branched glucans such as glycogen and amylopectin but low affinity for amylose and maltodextrin.26,27 The potato tuber enzyme can act on amylose, amylopectin, and maltodextrin but only poorly on glycogen,28,29 while the E. coli enzyme shows high affinity for maltodextrin.10 ... 

Muscle phosphorylase synthesizes an amylose from a-n-glucopyranosyl phosphate, whilst impure heart and liver preparations give polysaccharides with the physicochemical properties of a glycogen (ref. 27). 

Methods of assay (m) = methylation (p) = periodate oxidation (e) = enzymic. B.V. = Blue Value (compare Refs. 3 and 4). Xmax = wavelength of maximum absorption of polysaccharide-iodine complex. Priming activity toward P-enzyme soluble starch = 1.0. Priming activity toward muscle phosphorylase glycogen = 100, corn amylopectin = 63. Molecular weight, 64,000 (compared with about 100,000 for the parent amylose). 

Numerous analogs of carbohydrate polymers (i.e., amylose, glycogen) have been prepared from modified monosaccharide 1-phosphates with phosphorylase (Fig. 13-11 shows the natural substrates) l159 162l. 

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