The extension of alpha-D-1,3-branch linkages by 1,3-alpha-D-glucan synthase from Streptococcus sobrinus.
In the presence of an acceptor, 1,3-alpha-D-glucan synthase of Streptococcus sobrinus synthesizes water-insoluble glucans from sucrose. Under such conditions, 1,3-alpha-D-glucoside linkages were extended without any change in the glucose-residue number between the 1,3,6-branch points on the acceptor. From these results, the mechanisms of water-insoluble-glucan formation were proposed as follows: (i) the attachment of an acceptor to the glucan binding sites of 1,3-alpha-D-glucan synthase occurs during the initiation of the reaction, and concurrently determines the positions of the branched portions of 1,3,6 on the acceptor, and (ii) the 1,3-alpha-D-glucoside linkage extends from these positions.
Takehara
T
T
Department of Preventive Dentistry, Kyushu Dental College, Japan.
Ansai
T
T
Kunimori
A
A
Yamashita
Y
Y
Hanada
N
N
D002236:Carbohydrate Conformation; D005936:Glucans / Q000096:biosynthesis*; D005964:Glucosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008745:Methylation; D013291:Streptococcus / Q000201:enzymology*
D005936:Glucans; C036655:1,3-alpha-D-glucan synthase; D005964:Glucosyltransferases