Enzyme activity: Gtfa163 Glucansucrase (Reuteransucrase) catalyses the transfer of glucose from sucrose to make a highly branched, high-molecular-weight α-D-glucan with α(1→4) glucosidic linkages but also some α(1→6)-linked glucosyl units and 4,6-disubstituted glucosyl units at the branching points.

As an example, glucose transferase activity was determined at 50°C for 60 hours in a 25 mM sodium acetate buffer at pH 4.7, containing 1 mM CaCl2 and 100 mM sucrose. This gave complete utilization of the sucrose with about 75% going into α-D-glucan.

Activity determination: Glucansucrase activity was determined at 50°C in a 25 mM sodium acetate buffer at pH 4.7, containing 10 mM CaCl2 and 30 nM enzyme.

Unit definition: One unit (U) of enzyme activity is the amount that leads to the release of 1 μmol of fructose from sucrose per minute.

Synonyms: glycoside hydrolase, glucosyltransferase, 4,6-alpha-Glucanotransferase, Reuteransucrase

Protein family: Glycosyl hydrolase family 70 ( GH70 ) – GH-H clan – CAZy database GH70 family

Enzyme classification: EC 2.4.1.-

Source: The lactic acid bacteria Lactobacillus reuteri strain 121

Protein sequence: NBCI protein entry

Structural information: The crystal structure of Gtfa163 Glucansucrase (Reuteransucrase) from Lactobacillus reuteri121 has been determined and shown here in Figure 1 (Pijning et al. 2012). – PDB entry 4AMC