title: Bacillus macerans cyclomaltodextrin glucanotransferase transglycosylation reactions with different molar ratios of D-glucose and cyclomaltohexaose.
abstract: It was found that Bacillus macerans cyclomaltodextrin glucanotransferase (CGTase) reacts with cyclomaltohexaose (alpha-cyclodextrin, alpha-CD) to give a series of cyclomaltooligosaccharides (cyclomaltodextrins, CDs), having seven to more than 20 D-glucose residues and maltooligosaccharides (maltodextrins, MDs) from G5 to G12+. When D-glucose (Glc) was added to the alpha-CD at very low molar ratios (1:100) of Glc to alpha-CD, the predominant products (95%) were CDs, some of which were macrocyclic MDs with 20-60 D-glucose residues, along with MDs that also had high molecular weights, containing 10-75 D-glucose residues and gave a blue iodine-iodide color. As the molar ratio of Glc to alpha-CD was increased, the amount of CDs progressively decreased and MDs proportionately increased in the range of G2-G12. At 25 mM alpha-CD and Glc to alpha-CD molar ratio of 1:1, a 75% yield of MDs, G1-G12, each in approximately equal amounts, was obtained; and at 20 mM and a 5:1 ratio, a 97% yield of MDs, G2-G9, was obtained but in unequal amounts. At higher ratios (10:1), the CDs completely disappeared, and at very high ratios (50:1 to 100:1) only low-molecular-weight MDs, G2-G4, were formed.
authors.affiliation: Laboratory of Carbohydrate Chemistry and Enzymology, 4252 Molecular Biology Bldg, Iowa State University, Ames, IA 50011, USA.
authors.forename: Seung-Heon
authors.initials: SH
authors.lastname: Yoon
authors.forename: John F
authors.initials: JF
authors.lastname: Robyt
mesh_terms: D001407:Bacillus / Q000201:enzymology / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D003505:Cyclodextrins / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism*; D006031:Glycosylation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D047391:alpha-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D047391:alpha-Cyclodextrins; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D005947:Glucose; C032613:alpha-cyclodextrin