1,4-alpha-glucan branching enzyme TTHA1902

UniProtKB accession:  Q5SH28

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UniProtKB description:  Catalyzes the formation of branch points in alpha-glucans by cleavage of an alpha-1,4 glycosidic bond and subsequent transfer of the cleaved-off oligosaccharide to a new alpha-1,6 position. The branch chain-length distribution of the reaction products shows degree of polymerization (DP) of 3 to 13, with two local maxima at DP 7 and DP 11. Exhibits an alpha-retaining catalytic mechanism. Is involved in glycogen biosynthesis. Shows a secondary activity, i.e. the hydrolysis of the substrate, being 4% of the total activity. Can use amylose as substrate but not alpha-1,4-linked oligosaccharides of 2-7 glucose residues, beta-cyclodextrin, 6-O-glucosyl-beta-cyclodextrin and 6-O-maltosyl-beta-cyclodextrin. Is not able to branch amylopectin further, it only hydrolyzes amylopectin. Thus, displays preference for linear and long substrates (amylose) over branched structures (amylopectin).