A Study of the Constitution of Alginic Acid by Partial Acid Hydrolysis.

Haug, Arne; Lársen, Bjørn; Smidsrød, Olav; Møller, Jørgen; Brunvoll, J.; Bunnenberg, E.; Djerassi, Carl; Records, Ruth

doi:10.3891/acta.chem.scand.20-0183

Cited by 473 publications

(132 citation statements)

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“…The values were in good agreement with those reported by Haug et al 10 ) Acid hydrolysis of PM and PG was undertaken to obtain a series of oligomers with various * Abbreviations: PM, poly ,B-l,4-o-mannuronanate; PG, poly a-l,4-L-guluronate; Mi and G i (i= 1 to 7) corresponding to monomer to heptamer of mannuronate and guluronate, respectively. molecular sizes including monomers.…”

Section: Preparation Of Oligomerssupporting

confidence: 76%

“…PM and PG were prepared by the method of Haug et al 10 ) Sephadex G-15 and Bio-Gel P-2 were the products of Pharmacia Fine Chemicals AB, Uppsala (Sweden) and of Bio-Rad Laboratories, Richmond (U.S.A.), respectively. Other materials were the purest grade commercially available.…”

Section: Methodsmentioning

confidence: 99%

“…PM and PG (2g each) prepared from alginate by the method of Haug et al,10) were separately hydrolyzed with 20ml of 70% H 2 S0 4 at 30°C for 25 (PM) and 90 min (PG). Intermittent mechanical stirring of the reaction mixtures is recommended during hydrolysis.…”

Section: Methodsmentioning

confidence: 99%

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Action of Poly(β-D-mannuronate)lyase fromTurbo cornutuson Oligomeric Substrates

Muramatsu

Yamada

Date

et al. 1993

Bioscience, Biotechnology, and Biochemistry

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Section: Preparation Of Oligomerssupporting

confidence: 76%

Section: Methodsmentioning

confidence: 99%

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Action of Poly(β-D-mannuronate)lyase fromTurbo cornutuson Oligomeric Substrates

Muramatsu

Yamada

Date

et al. 1993

Bioscience, Biotechnology, and Biochemistry

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“…[1][2][3][4] There are three types of dyad sequential blocks as MM, GG, and MG. These residue sequences endow with the alginate chain different stiffness, e.g., that the mean square end-to-end distance per uronate residue for G component is 2.2 times larger than that for the M component.…”

Section: Introductionmentioning

confidence: 99%

Sol–Gel Transition in Aqueous Alginate Solutions Induced by Cupric Cations Observed with Viscoelasticity

Liu

Qian

et al. 2003

Polym J

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ABSTRACT:Sol-Gel transition was occurred in 2 wt% aqueous solutions of four alginate samples with different molecular weight M w and the ratio M/G of repeat unit mannuronate (M) to guluronate (G) induced by adding cupric ions. The transition was monitored with dynamic moduli G and G in the linear region of viscoelasticity and the gel point was determined according to the Winter's criterion where the loss angle tan δ became independent of frequency ω. The mole ratio of Cu 2+ to the carboxyl group in alginate at gel point, f gel , was higher for the samples with lower molecular weight than those with higher molecular weight without obvious M/G dependence. This suggested there was no M/G selection of Cu 2+ complex formation with alginate. The relaxation critical exponent n for alginate samples with higher G content was lower than 0.5, meaning G > G for the critical gels with a denser network. The cupric ion number relevant to one alginate chain at the gel point, N gel , was estimated from f gel M n /M 0 and reflected the gel elasticity.KEY WORDS Alginate / Cupric Cations / Sol-Gel Transition / Critical Exponent / Dynamic Viscoelasticity / Alginate is a natural polysaccharide consisting of β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) residues (Figure 1) (1→4) linked in a nonregular blockwise pattern along the linear chain and is mainly used as a gelling agent in numerous food and pharmaceutical applications. [1][2][3][4] There are three types of dyad sequential blocks as MM, GG, and MG. These residue sequences endow with the alginate chain different stiffness, e.g., that the mean square end-to-end distance per uronate residue for G component is 2.2 times larger than that for the M component. 5 The chemical composition and sequence of the M and G residues depend on the biological source and growth and seasonal conditions. 1,2 The most attractive ability of alginate is the gel formation induced by adding various divalent cations, except Mg 2+ . 6 The gelation behavior and gel strength of aqueous alginate solutions strongly depend on the content of guluronate residues and also on the molecular weight and molecular weight distribution of alginates. [6][7][8] Matsumoto and Mashiko investigated the influence of added salts on the viscoelastic properties of aqueous alginate solution and argued that the interaction between alginate and metal cations did not work as the cross-linking point. 8 Matsumoto et al. also followed the gelation process in sodium alginate solutions induced by increasing polymer concentration without any divalent cations and found the promoting effect to the gelation of chain stiffness, i.e., the alginate with higher G residue content formed gel at lower concentration with more perfect structure. 9, 10 By viscometry, † To whom correspondence should be addressed.

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“…Sodium alginate (1000 cps grade) was obtained from Nacalai Tesque Inc., Tokyo, Japan, and the mannuronic acid/guluronic acid ratio of the preparation was estimated to be 1.25 by measuring circular dichroic ellipticity.15) PM and PG were prepared from sodium alginate, by the method of Haug et al 16 ) The average degrees of polymerization of PG and PM were 24 and 22, respectively, based on the reducing end group analysis, to which a modified Somogyi-Nelson's method was applied. 17 ) DEAE-Cellulofine, Cellulofine GCLlOOOm, and Butyl-Cellulofine were purchased from Seikagaku Corp., Tokyo, Japan.…”

Section: Methodsmentioning

confidence: 99%