A d-glucosylated form of dextransucrase: Demonstration of partial reactions

✍ Scribed by Gary A. Luzio; Veena K. Parnaik; Robert M. Mayer

• Book ID: 102640186
• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 460 KB
• Volume: 121
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(83)84023-3

✦ Synopsis

A D-glucosylated form of dextransucrase, whose preparation and characteristics have just been reported in Carbohydr. Res., was employed in a series of studies designed to explore the question of whether the bound sugars participate in the reactions catalyzed by the enzyme. When exposed to maltose, a good acceptor-substrate, monomeric D-glucosyl groups were rapidly transferred to the disaccharide, affording a trisaccharide. In the absence of an acceptor, monomeric D-glucose was released from the enzyme by hydrolysis. In a reaction with D-fructose, the charged enzyme catalyzed the formation of sucrose. Finally, in the presence of unlabeled sucrose, monomeric D-glucosyl groups were chased into enzyme-associated oligomers. Evidence is also presented which indicates that the various pathways for the bound D-glucosyl groups are competitive. The significance of these observations is discussed.