The triple-stranded polysaccharide scleroglucan was subjected to free-radical
depolymerisation with Fenton's reagent (H2O2/Fe2+), and partially
degraded samples in the molecular weight (M-w) range from 8 200 000
to 5200 were studied. Analyses of the chemical composition of partially
degraded samples by C-13 nuclear magnetic resonance spectroscopy
and by determination of reducing end-groups suggested that the degradation
was random. The decrease in M-w followed the kinetics expected for
a multiple-stranded polymer. Following an apparently initial stable
regime, degradation occurred with an exponential decrease (exponent
(nu) similar to 3.6) in M-w. Partially degraded samples displayed
bimodal molecular weight distributions. This was attributed to the
release of single-stranded oligomers having a degree of polymerisation
(DP) too low to remain incorporated in the tripler structure (DP
< DP,; the critical lower DP far tripler formation). The weight-average
molecular weight of the low-M-w fraction was estimated to about 36
000 (DP(w)similar to 56 tetrasaccharide units). Following a heat
treatment at 100 degrees C (15 min) of the partially degraded samples,
a reduction in M-w by a factor of 2 to 2.5 was observed. This was
attributed to the formation of more perfectly matched triple-stranded
molecules, without aggregation or ring formation, as shown by electron
microscopy. (C) 1998 Elsevier Science Ltd. All rights reserved.
%0 Journal Article
%1 Hjerde1998
%A Hjerde, T.
%A Stokke, B. T.
%A Smidsrod, O.
%A Christensen, B. E.
%C THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND
%D 1998
%I ELSEVIER SCI LTD
%J Carbohydr. Polym.
%K ; ;; [ISI:] acid-hydrolysis; aqueous-solution; conformational degradation; depolymerization; ferrous free-radical ions microscopy; polysaccharide; schizophyllan; scleroglucan; transitions; viscosity xanthan;
%N 1
%P 41 -- 48
%T Free-radical degradation of triple-stranded scleroglucan by hydrogen
peroxide and ferrous ions
%V 37
%X The triple-stranded polysaccharide scleroglucan was subjected to free-radical
depolymerisation with Fenton's reagent (H2O2/Fe2+), and partially
degraded samples in the molecular weight (M-w) range from 8 200 000
to 5200 were studied. Analyses of the chemical composition of partially
degraded samples by C-13 nuclear magnetic resonance spectroscopy
and by determination of reducing end-groups suggested that the degradation
was random. The decrease in M-w followed the kinetics expected for
a multiple-stranded polymer. Following an apparently initial stable
regime, degradation occurred with an exponential decrease (exponent
(nu) similar to 3.6) in M-w. Partially degraded samples displayed
bimodal molecular weight distributions. This was attributed to the
release of single-stranded oligomers having a degree of polymerisation
(DP) too low to remain incorporated in the tripler structure (DP
< DP,; the critical lower DP far tripler formation). The weight-average
molecular weight of the low-M-w fraction was estimated to about 36
000 (DP(w)similar to 56 tetrasaccharide units). Following a heat
treatment at 100 degrees C (15 min) of the partially degraded samples,
a reduction in M-w by a factor of 2 to 2.5 was observed. This was
attributed to the formation of more perfectly matched triple-stranded
molecules, without aggregation or ring formation, as shown by electron
microscopy. (C) 1998 Elsevier Science Ltd. All rights reserved.
@article{Hjerde1998,
__markedentry = {[phpts:6]},
abstract = {The triple-stranded polysaccharide scleroglucan was subjected to free-radical
depolymerisation with Fenton's reagent (H2O2/Fe2+), and partially
degraded samples in the molecular weight (M-w) range from 8 200 000
to 5200 were studied. Analyses of the chemical composition of partially
degraded samples by C-13 nuclear magnetic resonance spectroscopy
and by determination of reducing end-groups suggested that the degradation
was random. The decrease in M-w followed the kinetics expected for
a multiple-stranded polymer. Following an apparently initial stable
regime, degradation occurred with an exponential decrease (exponent
(nu) similar to 3.6) in M-w. Partially degraded samples displayed
bimodal molecular weight distributions. This was attributed to the
release of single-stranded oligomers having a degree of polymerisation
(DP) too low to remain incorporated in the tripler structure (DP
< DP,; the critical lower DP far tripler formation). The weight-average
molecular weight of the low-M-w fraction was estimated to about 36
000 (DP(w)similar to 56 tetrasaccharide units). Following a heat
treatment at 100 degrees C (15 min) of the partially degraded samples,
a reduction in M-w by a factor of 2 to 2.5 was observed. This was
attributed to the formation of more perfectly matched triple-stranded
molecules, without aggregation or ring formation, as shown by electron
microscopy. (C) 1998 Elsevier Science Ltd. All rights reserved.},
added-at = {2011-11-04T13:47:04.000+0100},
address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND},
author = {Hjerde, T. and Stokke, B. T. and Smidsrod, O. and Christensen, B. E.},
authoraddress = {Norwegian Univ Sci & Technol, Dept Biotechnol, NTNU, N-7034 Trondheim,
Norway. ; Norwegian Univ Sci & Technol, Dept Phys, NTNU, N-7034 Trondheim,
Norway.},
biburl = {https://www.bibsonomy.org/bibtex/286221076300ad270c9d8838c76dcc1bb/pawelsikorski},
citedref = {BOHN JA, 1995, CARBOHYD POLYM, V28, P3 ; CHRISTENSEN BE, 1991, CARBOHYD
RES, V214, P55 ; CHRISTENSEN BE, 1993, MACROMOLECULES, V26, P6111
; CHRISTENSEN BE, 1996, CARBOHYD RES, V280, P85 ; CHRISTENSEN BE,
1996, MACROMOLECULES, V29, P2939 ; DAVISON P, 1982, SOC PET ENG J
JUN, P353 ; DUBOIS M, 1956, ANAL CHEM, V28, P350 ; HERP A, 1967,
CARBOHYD RES, V4, P63 ; HJERDE T, 1994, CARBOHYD POLYM, V24, P265
; HJERDE T, 1996, CARBOHYD RES, V288, P175 ; HJERDE T, 1998, MACROMOLECULES,
V31, P1842 ; HODGE JE, 1962, METHODS CARBOHYDRATE, V1, P380 ; KITAMURA
S, 1989, BIOPOLYMERS, V28, P639 ; KITAMURA S, 1996, BIOPOLYMERS,
V39, P407 ; KNUTSEN SH, 1993, HYDROBIOLOGIA, V260, P667 ; MCINTIRE
TM, 1995, MACROMOLECULES, V28, P6375 ; NORISUYE T, 1980, J POLYM
SCI POL PHYS, V18, P547 ; RINAUDO M, 1980, INT J BIOL MACROMOL, V2,
P45 ; RINAUDO M, 1982, CARBOHYD POLYM, V2, P135 ; SHARPLES A, 1957,
T FARADAY SOC, V53, P1003 ; SMIDSROD O, 1965, ACTA CHEM SCAND, V19,
P143 ; STOKKE BT, 1992, MACROMOLECULES, V25, P2209 ; STOKKE BT, 1993,
BIOPOLYMERS, V33, P193 ; STOKKE BT, 1994, MICRON, V25, P469 ; THOMAS
CA, 1956, J AM CHEM SOC, V78, P1861 ; TYLER JM, 1980, J ULTRASTRUCT
RES, V71, P95 ; UCHIYAMA H, 1990, J BIOL CHEM, V265, P7753 ; WELLINGTON
SL, 1983, SOC PET ENG J DEC, P901 ; YANAKI T, 1983, BIOPHYS CHEM,
V17, P337},
interhash = {6adda4ae75b37d9d6fdce80b6b8775ab},
intrahash = {86221076300ad270c9d8838c76dcc1bb},
isifile-dt = {Article},
isifile-ga = {136AK},
isifile-j9 = {CARBOHYD POLYM},
isifile-nr = {29},
isifile-pi = {OXFORD},
isifile-rp = {Christensen, BE, Norwegian Univ Sci & Technol, Dept Biotechnol, NTNU,
; N-7034 Trondheim, Norway.},
isifile-sc = {Chemistry, Applied; Chemistry, Organic; Polymer Science},
isifile-tc = {6},
issn = {0144-8617},
journal = {Carbohydr. Polym.},
keywords = {; ;; [ISI:] acid-hydrolysis; aqueous-solution; conformational degradation; depolymerization; ferrous free-radical ions microscopy; polysaccharide; schizophyllan; scleroglucan; transitions; viscosity xanthan;},
language = {English},
month = SEP,
number = 1,
owner = {phpts},
pages = {41 -- 48},
publisher = {ELSEVIER SCI LTD},
size = {8 p.},
sourceid = {ISI:000076835300006},
timestamp = {2011-11-04T13:47:12.000+0100},
title = {Free-radical degradation of triple-stranded scleroglucan by hydrogen
peroxide and ferrous ions},
volume = 37,
year = 1998
}