The kinetic behavior of soluble and insoluble forms of dextransucrase from Leuconostoc mesenteroides NRRL B-1299 was investigated with sucrose as substrate and maltose as acceptor. To study the parameters involved, a kinetic model was applied that was previously developed for L. mesenteroides NRRL B-512F dextransucrase. There are significant correlations between the parameters of the soluble form of B-1299 dextransucrase and those calculated for the B-512F enzyme; that is, their properties are comparable and differ from those of the insoluble form of B-1299 dextransucrase. Whereas the calculated parameters for high maltose concentrations describe the kinetic behavior very well, the time curves for low maltose concentrations were not described correctly. Therefore, the parameters were calculated separately for the two ranges.