Oligosaccharides embodying the S-maltosyl-6-thiomaltosyl structure have been readily synthesised by using convergent chemoenzymatic approaches. The key steps for the preparation of these molecules involved: 1) transglycosylation reactions of maltosyl fluorides onto suitable acceptors catalysed by the bacterial transglycosylase, cyclodextrin glycosyltransferase (CGTase), and 2) the SN2-type displacement of a 6-halide from acetylated acceptors by activated 1-thioglycoses. The target molecules, which were obtained in good overall yields, proved to be useful for investigating substrate binding in the active sites of several enzymes that act upon the alpha-1,6-linkage of pullulan and/or amylopectin. The compounds exhibit Ki values in the 2.5-1350 microM range with the different enzymes, and the highest affinity found by using these molecules was seen for the pullulanase from Bacillus acidopullulyticus. Both barley-malt limit dextrinase and pullulanase type II from Thermococcus hydrothermalis only recognised the longest linear thiooligosaccharide, while a branched heptasaccharide was the strongest inhibitor of pullulanase from Klebsiella planticola.
|Publication status||Published - 2002|
Greffe, L., Jensen, M. T., Chang-Pi-Hen, F., Fruchard, S., O'Donohue, M. J., Svensson, B., & Driguez, H. (2002). Chemoenzymatic syntheses of linear and branched hemithiomaltodextrins as potential inhibitors for starch-debranching enzymes. Chemistry, 8, 5447-5455. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=12561317&query_hl=34&itool=pubmed_docsum