Influence of ursolic acid on glucooligosaccharides synthesized by dextransucrase from Leuconostoc mesenteroides Lm 28

A study of modulation of the reactions catalyzed by dextransucrase from Leuconostoc mesenteroides Lm 28 strain in the presence of triterpenoid ursolic acid was carried out. This compound showed concentration dependent inhibition of the studied dextransucrase and Ki = 1.9 mM, which is about 5 times higher than Ki value of the known glucansucrase inhibitor acarbose. Ursolic acid affected significantly the acceptor reactions catalyzed by Lm 28 dextransucrase in the presence of maltose and sucrose to maltose ratio 2. Increasing concentrations of ursolic acid shifted concentration and degree of polymerization (DP) distribution of the synthesized glucooligosaccharides (GOS) to acceptor products with DP ≤ 5. The oligosaccharide synthesis scheme applied in this study is a promising approach for production of GOS with controlled length of the chain.