Synthesis of novel heterobranched beta-cyclodextrins from 4(2)-O-beta-D-galactosyl-maltose and beta-cyclodextrin by the reverse action of pullulanase, and isolation and characterization of the products.
From the mixture of 4(2)-O-beta-D-galactosyl-maltose (Gal-G2) and beta-cyclodextrin (betaCD), novel heterobranched betaCDs, (Gal-G2)-betaCD and (Gal-G2)2-betaCDs, were synthesized by the reverse action of debranching enzyme. The optimum conditions for the production of (Gal-G2)2-betaCDs were examined. A mixture of (Gal-G2)2-betaCDs was produced in about 4% yield when Aerobacter aerogenes pullulanase (64 units per 1 g of Gal-G2) was incubated with 1.6 M Gal-G2 and 0.16 M betaCD at 50 degrees C for 4 days. The reaction products, (Gal-G2)2-betaCDs, were separated into three peaks by HPLC analysis on a Hypercarb S column. Their structures were analyzed by fast atom bombardment mass spectroscopy and NMR spectroscopies, and confirmed by comparison of their hydrolyzates by beta-galactosidase with the authentic (G2)2 -betaCDs. The structures of (Gal-G2)-betaCD and three components of (Gal-G2)2-betaCDs were identified as 6-O-(GalG2)-betaCD, 6(1),6(2)-, 6(1),6(3)- and 6(1),6(4)-di-O-(Gal-G2)2-betaCD, respectively.
Kitahataa
S
S
Osaka Municipal Technical Research Institute, Osaka, Japan. kitahata@omtri.city.osaka.jp
Tanimoto
T
T
Ikuta
A
A
Tanaka
K
K
Fujita
K
K
Hashimoto
H
H
Murakami
H
H
Nakano
H
H
Koizumi
K
K
D002240:Carbohydrate Sequence; D003505:Cyclodextrins / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D021902:Enterobacter aerogenes / Q000201:enzymology; D006026:Glycoside Hydrolases / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D016339:Spectrometry, Mass, Fast Atom Bombardment; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D047392:beta-Cyclodextrins; D006026:Glycoside Hydrolases; C100181:pullulanase; C031215:betadex