Dextrin dextranase
In enzymology, a dextrin dextranase is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are (1,4-alpha-D-glucosyl)n and (1,6-alpha-D-glucosyl)m, whereas its two products are (1,4-alpha-D-glucosyl)n-1 and (1,6-alpha-D-glucosyl)m+1.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is 1,4-alpha-D-glucan:1,6-alpha-D-glucan 6-alpha-D-glucosyltransferase. Other names in common use include dextrin 6-glucosyltransferase, and dextran dextrinase. If the enzyme predominantly catalyzes the synthesis of dextran from dextrin, the name "dextran dextrinase" is considered more appropriate.
In 2025, the three-dimensional structure of dextran dextrinase from Gluconobacter ''oxydans'' was reported. The enzyme shows a strong structural similarity to glucoamylases and glucodextranases, which hydrolyze dextrin and dextran. However, a spatial shift of about 1.5 Å in the catalytic residues enables dextran dextrinase to catalyze transglucosylation reactions.