Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
alpha(1-4) Glucan chain disposition in models of alpha(1-4)(1-6) glucans: comparison with structural data for mammalian glycogen and waxy amylopectin
Autore:
Matheson, NK; Caldwell, RA;
Indirizzi:
Univ Sydney, Dept Agr Chem & Soil Sci, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 il Sci, Sydney, NSW 2006, Australia
Titolo Testata:
CARBOHYDRATE POLYMERS
fascicolo: 3, volume: 40, anno: 1999,
pagine: 191 - 209
SICI:
0144-8617(199911)40:3<191:AGCDIM>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
STARCH-BRANCHING ENZYME; FINE-STRUCTURE; PSEUDOMONAS ISOAMYLASE; CONCANAVALIN-A; POTATO STARCH; AMYLOSE; MAIZE; FRACTIONS; GENOTYPES; (1->4)-ALPHA-D-GLUCANS;
Keywords:
chain distribution; random dendrimeric structure; alpha(1-4)(1-6) glucans; amylopectin; glycogen;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Matheson, NK Univ Sydney, Dept Agr Chem & Soil Sci, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 y, NSW 2006, Australia
Citazione:
N.K. Matheson e R.A. Caldwell, "alpha(1-4) Glucan chain disposition in models of alpha(1-4)(1-6) glucans: comparison with structural data for mammalian glycogen and waxy amylopectin", CARBOHY POL, 40(3), 1999, pp. 191-209

Abstract

Models of the chain distribution in alpha(1-4)(1-6) glucans-a regularly branched and a random dendrimeric structure, as well as variations of these in which the average frequency that B chains are branched by (1-6) linked chains (F), and the overall, internal, core and external average chain lengths resemble those of mammalian glycogen and waxy amylopectin have been generated. In the regularly branched model, with a total of T chains, when F is between I and 2 (e.g. glycogen) the numbers of each type of constituent chains (A, singly and doubly branched B), are Ta, Tb(2 - F) and Tb(F - 1) respectively, where a and b are the fractions of A and B chains. When F is between 2 and 3 (e.g. amylopectin) the numbers of A, doubly branched B and triply branched B chains are Ta, Tb(3 - F) and Tb(F - 2). The random dendrimeric model was obtained from an algorithm with varying probabilities assigned to extension and branching of A and B chains. The data produced included the fractions of A chains, of B chains with different levels of branching andof chains in tiers, and also the relative average lengths of A chains and segments of B chains between branches. In the random dendrimeric model the average fractions of chain types are: a,b(2),b(2)a,...,b(2)a(k-1) where thenumbers of branches in B chains (item 2 onwards) are the exponent of a plus one. Gaussian distributions of numbers of chains versus degree of polymerisation (in glucosyl units) (d.p.) have been constructed for each chain type fromtheir mean d.p. and average number of chains, and these distributions convolved to give a profile of numbers of alpha(1-4) chains versus their d.p. For rabbit liver glycogen, conversion to normalised curves of relative weight of glucan versus d.p. and comparison with normalised chromatographic elution profiles of debranched chains indicated that the curves of all the various regularly branched models differed markedly from those of the naturally-occurring polysaccharides. For this and waxy amylopectin a version of a random dendrimeric model was more appropriate than any of the regularly branched models and for the waxyamylopectin a significant difference in the experimental chain profile wasa subsidiary peak at the d.p. corresponding to B chains with four branchesin the model. (C) 1999 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 06:55:17