- HYDROLYSIS AND SYNTHESIS OF BRANCHED CYCLOMALTOHEXAOSES WITH Pseudomonas ISOAMYLASE
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The action of Pseudomonas isoamylase on branched cyclomaltohexaoses (α-cyclodextrins, cG6s) with side chains of various lengths and the reverse condensation reaction between malto-oligosaccharides (G2-G7) and cG6 have been studied.The rates of reaction for the liberation and the attachment of maltotriose were maximal in both the hydrolysis and the condensation reactions, and the activity decreased with increasing length of the side chain.The values of Vmax (U/mg) for the hydrolytic reactions for G2-, G3-, G4-, and G5-cG6 were 2.6, 690, 320, and 290, respectively, and the values of Km (mM) were 72, 204, 92, and 47, respectively.The structures of the new branched cG6s (G4-cG6 and G5-cG6), obtained through the condensation reaction, were identified by means of enzymic analyses, and 13C-n.m.r. and f.a.b.-mass spectra.The haemolytic activities of these branched cG6s are reported.
- Hizukuri, Susumu,Abe, Jun-Ichi,Koizumi, Kyoko,Okada, Yasuyo,Kubota, Yoko,et al.
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- ISOLATION AND CHARACTERIZATION OF BRANCHED CYCLODEXTRINS
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Three branched cyclodextrins (CDs) were isolated by high-performance liquid chromatography (l.c.) from the mother liquors of a large-scale preparation of the unbranched CDs with Bacillus ohbensis cyclomaltodextrin glucanotransferase.Evidence from chromatographic behavior on three l.c. coloumns of different separation modes, fragmentation analysis, 13C-n.m.r. spectroscopy, methylation analysis, and fast-atom bombardment-mass spectroscopy (f.a.b.-m.s.) indicated that these compounds were 6-O-α-D-glucopyranosylcyclomaltohexaose (1), 6-O-α-D-glucopyranosylcyclomaltoheptaose (2), and 6,6'''-di-O-α-D-glucopyranosylcyclomaltoheptaose (3).
- Koizumi, Kyoko,Utamura, Toshiko,Sato, Michikatsu,Yagi, Yoshiaki
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- Preparation and Enzymatic Hydrolysis of Maltosyl-α-cyclodextrin
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Maltosyl-α-cyclodextrin (6-α-maltosylcyclomaltohexaose, M-CD) was prepared from maltose and α-cyclodextrin by the reverse action of Bacillus pullulanase, and the action of α-amylases on this dextrin was examined.Among α-amylases tested, Thermoactinomyces vulgaris α-amylase (TVA) and Taka-amylase A (TAA) were found to attack the M-CD.Their action pattern on M-CD was studied.These α-amylases cleaved, first the cyclodextrin ring of M-CD, and the branched octasaccharides formed were immediately degraded to form glucose, branched tetraose, or pentaose, though the action pattern was different for TVA and TAA.In addition, TAA also split M-CD into glucose and glucosyl-α-cyclodextrin.Fission products at various stages of the reaction were separated and analyzed by paper chromatography and high performance liquid chromatography, their structures were analyzed, and the degradation pattern of M-CD was found.
- Sakano, Yoshiyuki,Sano, Mutsumi,Kobayashi, Tsuneo
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p. 3391 - 3398
(2007/10/02)
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