EC Number   |
Reaction |
Reference |
|---|
   2.4.1.4 | sucrose + [(1->4)-alpha-D-glucosyl]n = D-fructose + [(1->4)-alpha-D-glucosyl]n+1 |
alpha-retaining mechanism via a double-displacement similar to that described for alpha-amylases |
489147 |
| 2.4.1.4 | sucrose + [(1->4)-alpha-D-glucosyl]n = D-fructose + [(1->4)-alpha-D-glucosyl]n+1 |
DgAS binds the furanoid tautomers of fructose through a weak network of interactions to enable turanose formation. Such topology at subsite +1 is likely favoring other possible fructose binding modes as reported for Neisseria polysaccharea NpAS in agreement with the higher amount of trehalulose formed by DgAS. Residues Glu326 and Asp284 of DgAS are the general acid/base and the nucleophile, respectively, involved in the formation of the beta-glucosyl intermediate occurring in the alpha-retaining mechanism |
720052 |
| 2.4.1.4 | sucrose + [(1->4)-alpha-D-glucosyl]n = D-fructose + [(1->4)-alpha-D-glucosyl]n+1 |
in Neisseria polysaccharea NpAS key residues force the fructosyl moiety to bind in an open state with the O3' ideally positioned to explain the preferential formation of turanose by NpAS. Residues Glu328 and Asp286 of NpAS are the general acid/base and the nucleophile, respectively, involved in the formation of the beta-glucosyl intermediate occurring in the alpha-retaining mechanism |
720052 |
| 2.4.1.4 | sucrose + [(1->4)-alpha-D-glucosyl]n = D-fructose + [(1->4)-alpha-D-glucosyl]n+1 |
the elongation mechanism involves enzyme conformational changes to allow the entry of sucrose to the active site |
735389 |
