D-Glucanotransferase

Cyclodextrin n-Glucanotransferase.—Cyclodextrin D-glucanotransferase has been prepared from culture fluids of a Bacillus species by adsorption onto corn starch, fractional precipitation with ammonium sulphate, ion-exchange chromatography, and gel filtration. Disc electrophoresis and isoelectric focusing separated the enzyme into two fractions (p7 6.07 and 6.80), which were able to synthesize cycloamyloses (predominantly cyclohepta-amylose) from starch. The enzymes differ from the cyclodextrin o-glucanotransferase from B. macerans, notably in their actions on starch. 

Dextransucrases.—Dextransucrase has been obtained from culture fluids of Streptococcus mutans by fractional precipitation with ammonium sulphate, ion-exchange chromatography, and isoelectric focusing (p/4.0). The enzyme (mol. wt. 9.4 X 10 ) exhibited a broad temperature optimum (34—42 °C) and displayed maximum activity at pH 5.5. D-Fructose competitively inhibited the dextransucrase 27 mmol 1 ), which normally uses sucrose Km 3 mmol 1 ) as a substrate. Another report has also described the purification of dextransucrase from S. mutans by gel filtration and ion-exchange chromatography.  

Kitahata, N. Tsuyama, and S. Okada, Agric. and Biol. Chem. Japan), 1974, 38, 387. 

This preparation was homogeneous on examination by polyacrylamide gel electrophoresis and immunodiffusion, but gave two bands (mol. wt. 1.6 x 10 and 1.7 X 10 ) on electrophoresis in the presence of sodium dodecyl sulphate. The enzyme displayed maximum activity at pH 5.25. Immunoglobulins IgA from human saliva and colostrum accelerated the enzymic action, whereas serum immunoglobulins IgA and IgG were without effect. Two distinct forms of dextransucrase activity have been isolated from cells of S, mutans grown on D-glucose.  

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Cyclomaltodextrin D-Glucanotransferases. — Intermolecular transglycosylation of cyclomaltodextrin glycosyltransferase from Bacillus megaterium has been exam-... 

An acid cyclodextrin D-glucanotransferase from an alkalophilic Bacillus sp. exhibits a specificity similar to those of the transferases from B. circulans and B. macerans, although different proportions of cyclohexa-, cyclohepta-, and cyclo-octa-amyloses are formed. The cyclodextrin D-glucanotransferase from an alkalophilic Bacillus sp. has been used, either alone or in combination with pullul-anase, to produce cyclohepta-amylose. A succinylated derivative of this cyclodextrin D-glucanotransferase has been immobilized, with retention of activity, by adsorption onto a vinylpyridine polymer. 

The conversion of starch into cyclohepta-amylose by soluble or immobilized cyclodextrin D-glucanotransferases and the ability of a-amylases to convert starch into some products by a non-hydrolytic (transglycosylation) pathway have been reported.The production of single-cell protein from starchy wastes has been discussed. 

Cyclodextrin D-Glucanotransferases.—A succinyl derivative has been prepared from the cyclodextrin D-glucanotransferase isolated from an alkalophilic Bacillus species. ... 

An immobilized form of cyclodextrin D-glucanotransferase catalysed the conversion of starch into cyclohepta-amylose in a yield of 46 %, without significant loss of enzymic activity a yield of 52% was achieved when pullulanase was also added. ... 

Cyclodextrin D-Glucanotransferases.—The neutral cyclodextrin D-glucano-transferase from an alkaliphilic Bacillus species has been purified by adsorption onto starch, ion-exchange chromatography, gel filtration, and polyacrylamide gel electrophoresis. The enzyme (mol. wt. 8.5—8.8 x 10 in the presence of sodium dodecyl sulphate) is most active at pH 7 and 50 °C, is thermally stable, and converts starches and glycogens principally into cyclohepta-amylose. 

A purified extracellular cyclodextrin D-glucanotransferase (pH optimum 4.6, pi 5A, mol. wt. 8.8 x 10 ) from an alkaliphilic Bacillus species has been shown to be a single homogeneous protein by polyacrylamide gel electrophoresis and ultracentrifugation. The Km values for cyclohexa-, cyclohepta-, and cyclo-octa-amyloses at a constant concentration of sucrose are 5.88, 0.39, and 0.25 mmol 1, respectively. The enzyme converted starch, amylopectin, glycogen, and amylopectin j8-limit dextrin into cyclodextrins. 

The transglycosylation reactions catalysed by cyclodextrin D-glucano-transferases from B. megaterium and B. macerans have been shown to differ towards such acceptors as D-glucose, maltose, maltotriose, and sucrose. It was suggested that cyclodextrin D-glucanotransferase may transfer D-glucosyl residues from starch, as well as from cyclodextrins, to an acceptor. 

Cyclobuxine-D, 2 104 P-Cyclocitral, 24 570 Cyclocitronellene acetate, 24 488 a-Cyclocitrylidenebutanone, 24 565 Cyclodehydrating agents, 20 276 Cyclodemol, 24 488 P-Cyclodextrin, 4 715 Cyclodextrin glucanotransferase, 24 48 Cyclodextrin glycosyltransferase, 4 715 Cyclodextrin inclusions, 74 183 Cyclodextrin inclusion compounds, 74 166-167... 

Some starch-deficient mutants of Arabidopsis and Chlamydomonas have been shown to be defective in a-l,4-glucanotransferase activity. The enzyme is also known as D-enzyme. The reaction it catalyzes is as follows ... 

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