The reuteransucrase enzymes ofLactobacillus reuteristrain 121 (GTFA) andL. reuteristrain ATCC 55730 (GTFO) convert sucrose into a-d-glu-cans (labelled reuterans) with mainlya-(1fi4) glucosidic linkages (50% and 70%, respectively), plusa-(1fi6) linkages. In the present study, we report a detailed analysis of various hybrid GTFA⁄O enzymes, resulting in the iden-