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Studies on the Non‐cyclic Products of the Cyclodextrin Glycosyltransferase from Klebsiella pneumoniae M 5 al. Isolation and Characterization of Highly Branched Clusters from Digests with Manioc Starch
Author(s) -
Bender H.
Publication year - 1984
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19840360204
Subject(s) - klebsiella pneumoniae , isolation (microbiology) , glycosyltransferase , chemistry , starch , microbiology and biotechnology , biochemistry , biology , escherichia coli , enzyme , gene
Abstract 49.4% of manioc amylopectin was recovered as non‐cyclic products from 48 h digests of the starch with cyclodextrin glycosyltransferase [1, 4‐α‐D‐glucan: 1, 4‐α‐D‐glucopyranosyltransferase (cyclizing) EC 2.4.1.19] from Klebsiella pneumoniae M 5 al. Highly branched clusters of different sizes (average degree of polymerisation 26.9 ‐ 173) were obtained by fractionation. The extents of β‐amylolysis varied between 16.6 ‐ 23%, indicating that the cyclodextrin glycosyltransferase has left larger parts of unsubstituted (mainly A‐), and the exterior B‐chains. By debranching with pullulanase, and analysis of the linear chains, it was evident that the β‐limit dextrins of the fragments contained populations of longer chains, carrying branching points near the non‐reducing chain ends. From the molar distribution of the chains, calculated from the data obtained by quantitative h.p.l.c., indications of the structure of the branched fragments were obtained 3.5% of the amylopectin was found to be glucose to maltotetraose, indicating that coupling and disproportionation reactions were negligible even in the course of long‐term incubation. The smallest branched saccharides were found to be fragments with 6 D‐glucose residues.