Alternansucrase acceptor products

The regioselectivity of alternansucrase (EC 2.4.1.140) differs from dextransucrase (EC 2.4.1.5) in ways that can be useful for the synthesis of novel oligosaccharide structures. For example, it has been recently shown that the major oligosaccharides produced when maltose is the acceptor include one trisaccharide structure, two tetrasaccharides, one pentasaccharide, two hexasaccharides, one heptasaccharide, and at least two octasaccharides, containing no adjacent -(1 -> 3) linkages and no more than two consecutive alpha-(1 -> 6) linkages. This may shed some light on how the enzyme works to produce the alternating structure. Another characteristic of alternansucrase that distinguishes it from dextransucrase is its greater ability to use leucrose as an acceptor. Leucrose, produced by glucosyl transfer to fructose released from the initial sucrose substrate, represents a very poor substrate for Leuconostoc mesenteroides NRRL B-512F dextransucrase. Alternansucrase, however, continues to transfer glucosyl units to leucrose, resulting in some unusual glucosyl-fructose oligosaccharides.