Cyclodextrin glucosyltransferases

A more attractive chemo-enrymatic approach for the production of he-mithiocyclodextrins has been developed. More than ten years ago, cyclodextrin glucosyltransferase (CGTase) was shown to use a-maltosyl fluoride for the synthesis of a-, p-, and y-cyclodextrins [47] and has been used for the chemoenzymatic synthesis of regioselectively substituted cyclodextrins [48]. For this purpose, 4-thio-a-maltosyl fluoride (58) was easily prepared from (45). Incubation of (58) in the presence of pure CGTases afforded hemithiocyclodex-trins (57a), (57b) and (57c) isolated in 14,16 and 15% yields respectively [49]. 

Cyclodextrins are manufactured by the enzymatic degradation of starch using specialized bacteria. For example, P-cyclodextrin is produced by the action of the enzyme cyclodextrin glucosyltransferase upon starch or a starch hydrolysate. An organic solvent is used to direct the reaction that produces P-cyclodextrin, and to prevent the growth of microorganisms... 

Cyclodextrins are a special type of starch derivative. They come about as a result of the effect of the enzyme cyclodextrin glucosyltransferase on starch. Cyclic products result with 6,7 or 8 glucose units they are designated as a-, 6-, and y-cyclodextrin (Fig. 5.8). Although cyclodextrins are not naturally present in food, they will be considered here. In countries where they are permitted for food, they are used, e.g. for the encapsulation of flavourings and colourings and for masking off-flavours [24-29]. 

Zhang, QB, ZZ n and SZ Zhang (1998). Purification and properties of cyclodextrin glucosyltransferase from atkaliphilicbacteria. ActaMicrobiologica Sinica, 38(2), 98-102. (in Chinese)... 

This section does not aim to cover the cyclodextrins comprehensively the following however, are some references observed a monograph has been published on the compounds covering their structures, derivatives, inclusion compounds and methods of preparation and a collection of invited papers dealing mainly with inclusion complexes has appeared. Cyclodextrin glucosyltransferase applied to 6 -o-methyl-a-maltosyl fluoride yielded 6, 6 , 6 -tri-0-methylcyClomaltohexaose. Chemical approaches to the cyclodextrins have been reviewed, and a synthesis of cyclomannohexaose has been reported. ... 

Kabaivanova, L., Dobreva, E., Miteva, V. Production of cyclodextrin glucosyltransferase by Bacillus stearothermophilus R2 strain isolated from a Bulgarian hot spring. Journal of Applied Microbiology 1999, 86,1017-1023. 

P-D-Gal(l -3)-P-D-GalNAc( 1 -4)-P-D-Gal( 1 -4)-P-d-G1c cyclodextrin glucosyltransferase cation independent Cycloisomalto-octaose... 

S. is the generic name for such products as ->mal-todextrins, ->glucose syrups, - maltose syrups, - maltooligosaccharides, ->dextrose, - maltose. These starch sweeteners are produced by acid - hydrolysis or enzymatic - amylolysis. Additional modification of the product spectnun is achieved by isomerases (glucose isomerase) or by transferases (cyclodextrin glucosyltransferase). 

Stimulation of Cyclodextrin Glucosyltransferase (CGTase) in Production of Cyclodextrins... 

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