%0 Journal Article %1 Hjerde1998a %A Hjerde, T. %A Smidsrod, O. %A Stokke, B. T. %A Christensen, B. E. %C 1155 16TH ST, NW, WASHINGTON, DC 20036 USA %D 1998 %I AMER CHEMICAL SOC %J Macromolecules %K ;; [ISI:] chromatography; degradation depolymerization; gel-formation; helices; iota-carrageenan; poly-electrolytes; polysaccharides; size-exclusion transition; xanthan; %N 6 %P 1842 -- 1851 %T Acid hydrolysis of kappa- and l-carrageenan in the disordered and ordered conformations: Characterization of partially hydrolyzed samples and single-stranded oligomers released from the ordered structures %V 31 %X kappa- and iota-carrageenan that were partially hydrolyzed in dilute acid while being in the ordered conformation (induced by LiI or LiCl, respectively) gave rise to bimodal molecular weight distributions (MWDs) as shown by size-exclusion chromatography (SEC) and gel filtration. Optical rotation measurements showed that the high molecular weight (MW) fraction remained conformationally ordered, whereas the low-MW fraction was in the disordered state. The relative amount of the low-MW fraction increased with degradation time. By inducing the disordered conformation (in 0.01 M LiCl) the weight average molecular weight (M-w) of the partially hydrolyzed samples decreased 1.5-3 times. These results are interpreted in favor of a double-stranded ordered conformation. Partial hydrolysis of this structure yields a metastable, partially double-stranded structure containing chain breaks that are ünexposed" due to partial overlap of the individual chain fragments. When the degree of polymerization (DP) of such fragments decrease below the critical value (DPc) for duplex stabilization the fragments are released and appear as a separate low-MW fraction in the SEC chromatograms. DPc was estimated to be approximately 100 residues in both cases. After induction of the disordered conformation in partially hydrolyzed samples the molecular weight distribution remained bimodal. For kappa-carrageenan this is attributed to the higher rate of hydrolysis in the disordered fragments than in the parent ordered chains, which also leads to a rapid accumulation of dialyzable oligomers (DP 1-4). For iota-carrageenan, where the rate of hydrolysis ideally is independent of the conformational state, the bimodality is tentatively attributed to the presence of kappa-units (partially formed by desulfation), which are hydrolyzed more rapidly in the disordered state than in the ordered state.

@article{Hjerde1998a, __markedentry = {[phpts:6]}, abstract = {kappa- and iota-carrageenan that were partially hydrolyzed in dilute acid while being in the ordered conformation (induced by LiI or LiCl, respectively) gave rise to bimodal molecular weight distributions (MWDs) as shown by size-exclusion chromatography (SEC) and gel filtration. Optical rotation measurements showed that the high molecular weight (MW) fraction remained conformationally ordered, whereas the low-MW fraction was in the disordered state. The relative amount of the low-MW fraction increased with degradation time. By inducing the disordered conformation (in 0.01 M LiCl) the weight average molecular weight (M-w) of the partially hydrolyzed samples decreased 1.5-3 times. These results are interpreted in favor of a double-stranded ordered conformation. Partial hydrolysis of this structure yields a metastable, partially double-stranded structure containing chain breaks that are "unexposed" due to partial overlap of the individual chain fragments. When the degree of polymerization (DP) of such fragments decrease below the critical value (DPc) for duplex stabilization the fragments are released and appear as a separate low-MW fraction in the SEC chromatograms. DPc was estimated to be approximately 100 residues in both cases. After induction of the disordered conformation in partially hydrolyzed samples the molecular weight distribution remained bimodal. For kappa-carrageenan this is attributed to the higher rate of hydrolysis in the disordered fragments than in the parent ordered chains, which also leads to a rapid accumulation of dialyzable oligomers (DP 1-4). For iota-carrageenan, where the rate of hydrolysis ideally is independent of the conformational state, the bimodality is tentatively attributed to the presence of kappa-units (partially formed by desulfation), which are hydrolyzed more rapidly in the disordered state than in the ordered state.}, added-at = {2011-11-04T13:47:04.000+0100}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, author = {Hjerde, T. and Smidsrod, O. and Stokke, B. T. and Christensen, B. E.}, authoraddress = {Norwegian Univ Sci & Technol, Dept Biotechnol, Norwegian Biopolymer Lab, N-7034 Trondheim, Norway. ; Norwegian Univ Sci & Technol, Dept Phys, N-7034 Trondheim, Norway.}, biburl = {https://www.bibsonomy.org/bibtex/2544850e3f51eeda903fd6b9e00388904/pawelsikorski}, citedref = {ANDERSON NS, 1969, J MOL BIOL, V45, P85 ; AUSTEN KRJ, 1985, CARBOHYD RES, V140, P251 ; AUSTEN KRJ, 1988, BIOPOLYMERS, V27, P139 ; CHRISTENSEN BE, 1991, CARBOHYD RES, V214, P55 ; CHRISTENSEN BE, 1993, MACROMOLECULES, V26, P6111 ; CHRISTENSEN BE, 1996, CARBOHYD POLYM, V29, P217 ; CHRISTENSEN BE, 1996, CARBOHYD RES, V280, P85 ; CHRISTENSEN BE, 1996, MACROMOLECULES, V29, P2939 ; EKSTROM LG, 1985, CARBOHYD RES, V135, P283 ; GRASDALEN H, 1981, MACROMOLECULES, V14, P1842 ; HAWORTH WN, 1940, J CHEM SOC, P620 ; HJERDE T, 1994, CARBOHYD POLYM, V24, P265 ; HJERDE T, 1996, CARBOHYD RES, V288, P175 ; HJERDE T, 1998, IN PRESS BIOPOLYMERS ; HJERDE T, 1998, IN PRESS CARBOHYDR P ; IRING M, 1976, J POLYM SCI S, V57, P55 ; JONES RA, 1973, J CHEM SOC P2, P1608 ; KENNEDY JF, 1995, CARBOHYD POLYM, V26, P31 ; KNUTSEN SH, 1993, HYDROBIOLOGIA, V260, P667 ; MILLANE RP, 1988, CARBOHYD RES, V182, P1 ; MORRIS ER, 1980, J MOL BIOL, V138, P349 ; MULLER G, 1988, CARBOHYD POLYM, V9, P213 ; NERDAL W, 1993, J BIOMOL STRUCT DYN, V10, P785 ; NORTON IT, 1983, J CHEM SOC FARAD T 1, V79, P2475 ; NORTON IT, 1983, J CHEM SOC FARAD T 1, V79, P2501 ; PAOLETTI S, 1984, BIOPOLYMERS, V23, P1771 ; REES DA, 1963, BIOCHEM J, V88, P343 ; REES DA, 1969, ADV CARBOHYD CHEM BI, V24, P267 ; RINAUDO M, 1980, INT J BIOL MACROMOL, V2, P45 ; ROCHAS C, 1984, BIOPOLYMERS, V23, P735 ; SLOOTMAEKERS D, 1988, INT J BIOL MACROMOL, V10, P160 ; SMIDSROD O, 1980, CARBOHYD RES, V80, C11 ; SMIDSROD O, 1984, HYDROBIOLOGIA, V116, P178 ; SMIDSROD O, 1984, HYDROBIOLOGIA, V116, P19 ; SNOEREN THM, 1976, BIOCHIM BIOPHYS ACTA, V437, P264 ; STOKKE BT, 1992, MACROMOLECULES, V25, P2209 ; SWORN G, 1987, J CHROMATOGR, V403, P307 ; THOMAS CA, 1956, J AM CHEM SOC, V78, P1861 ; VANNESTE K, 1994, MACROMOLECULES, V27, P7496 ; VIEBKE C, 1995, CARBOHYD POLYM, V27, P145 ; YANAKI T, 1983, BIOPHYS CHEM, V17, P337}, interhash = {37a84926638dc14021820db200b14efb}, intrahash = {544850e3f51eeda903fd6b9e00388904}, isifile-dt = {Article}, isifile-ga = {ZE039}, isifile-j9 = {MACROMOLECULES}, isifile-nr = {41}, isifile-pi = {WASHINGTON}, isifile-rp = {Christensen, BE, Norwegian Univ Sci & Technol, Dept Biotechnol, ; Norwegian Biopolymer Lab, N-7034 Trondheim, Norway.}, isifile-sc = {Polymer Science}, isifile-tc = {21}, issn = {0024-9297}, journal = {Macromolecules}, keywords = {;; [ISI:] chromatography; degradation depolymerization; gel-formation; helices; iota-carrageenan; poly-electrolytes; polysaccharides; size-exclusion transition; xanthan;}, language = {English}, month = {MAR 24}, number = 6, owner = {phpts}, pages = {1842 -- 1851}, publisher = {AMER CHEMICAL SOC}, size = {10 p.}, sourceid = {ISI:000072751200018}, timestamp = {2011-11-04T13:47:12.000+0100}, title = {Acid hydrolysis of kappa- and l-carrageenan in the disordered and ordered conformations: Characterization of partially hydrolyzed samples and single-stranded oligomers released from the ordered structures}, volume = 31, year = 1998 }