Chemoenzymatic synthesis of 6ω-S-α-d-glucopyranosyl-6ω-thiomaltooligosaccharides: their binding to Aspergillus niger glucoamylase G1 and its starch-binding domain
✍ Scribed by Christine Apparu; Hugues Driguez; Gary Williamson; Birte Svensson
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 424 KB
- Volume
- 277
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
A coupling reaction of cyclodextrin glucosyltransferase (CGTase) with glucose and 6-deoxy-6-iodo-cyclomaltoheptaose (1), in the presence of glucoamylase, followed by acetylation, led to a convenient synthesis of acetylated 6III-deoxy-6III-iodo-maltotriose (2) and 6IV-deoxy-6IV-iodomaltotraose (3). Nucleophilic displacement of the iodine atom of these protected maltotriose and maltotetraose analogs by the activated form of 2,3,4,6-tetra-O-acetyl-1-S- acetyl-1-thio-alpha-D-glucose (4) afforded peracetylated 6III-S-alpha-D-glucopyranosyl-6III-thiomaltotriose (5) and 6IV-S-alpha-D-glucopyranosyl-6IV-thiomaltotetraose (6) in high yield. The interaction of OH-free tetra- and penta-saccharides (7 and 8) with both glucoamylase G1 from Aspergillus niger as well as its isolated starch-binding domain fragment were studied by UV difference spectroscopy. It was found that the starch-binding domain has higher affinity for 7 and 8 than for maltotetraose and maltopentaose.