Structure and solution properties of enzymatically synthesized glycogen.
Recently, a new enzymatic process for glycogen production was developed. In this process, short-chain amylose is used as a substrate for branching enzymes (BE, EC 2.4.1.18). The molecular weight of the enzymatically synthesized glycogen (ESG) depends on the size and concentration of the substrate. Structural and physicochemical properties of ESG were compared to those of natural source glycogen (NSG). The average chain length, interior chain length, and exterior chain length of ESG were 8.2-11.6, 2.0-3.3, and 4.2-7.6, respectively. These values were within the range of variation of NSG. The appearances of both ESG and NSG in solution were opalescent (milky white and slightly bluish). Furthermore, transmission electron microscopy and atomic force microscopy showed that ESG molecules formed spherical particles, and that there were no differences between ESG and NSG. Viscometric analyses also showed the spherical nature of both glycogens. When ESG and NSG were treated with pullulanase, a glucan-hydrolyzing enzyme known to degrade glycogen only on its surface portion, both glycogens were similarly degraded. These analyses revealed that ESG shares similar molecular shapes and surface properties with NSG.
Development Department, Food Material Division, Glico Foods Co. Ltd, 7-16 Kasuga-cho, Takatsuki, Osaka, Japan. kajiura-hideki@gf.glico.co.jp
Hideki
H
Kajiura
Hiroki
H
Takata
Takashi
T
Kuriki
Shinichi
S
Kitamura
D015061:1,4-alpha-Glucan Branching Enzyme / Q000378:metabolism; D000688:Amylose / Q000737:chemistry / Q000378:metabolism; D002850:Chromatography, Gel; D005936:Glucans / Q000737:chemistry / Q000378:metabolism; D006003:Glycogen / Q000737:chemistry* / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D014783:Viscosity
D005936:Glucans; D006003:Glycogen; D000688:Amylose; D015061:1,4-alpha-Glucan Branching Enzyme; D006026:Glycoside Hydrolases; C100181:pullulanase