3.2.1.B41 additional information the substrate can act not only as a glycosyl donor but also as a glycosyl acceptor. In addition, when the glucose is added to reaction mixtures, inhibition or activation is observed depending on both substrate concentration and temperature. A reaction model is proposed to explain the kinetic behavior of the enzyme. The scheme integrates the inhibition observed at high concentrations of substrate and the activation due to transglycosylation reactions implicating the existence of a transfer subsite 2