title: Structures of the amylopectins of waxy, normal, amylose-extender, and wx:ae genotypes and of the phytoglycogen of maize.
abstract: Average chain lengths and beta-amylolysis limits have been determined for the waxy and ae/wx genotypes of mature maize starch, and for the amylopectin fractions of normal and amylose-extender starches (prepared by precipitation with concanavalin A), rabbit-liver glycogen, phytoglycogen, and waxy rice starch. All amylopectin samples had similar A:B chain ratios of > 1 and the two glycogens had ratios of < 1. This finding led to average frequencies of substitution of B chains over the whole molecule of > 2 for the amylopectins and < 2 for the glycogens. An equation for the number of tiers for a molecule with various frequencies of substitution of B chains and chain lengths has been used to determine the effect of variation in average frequency of branching and average chain length on structure.
authors.affiliation: Department of Agricultural Chemistry, University of Sydney, NSW, Australia.
authors.forename: S H
authors.initials: SH
authors.lastname: Yun
authors.forename: N K
authors.initials: NK
authors.lastname: Matheson
mesh_terms: D000687:Amylopectin / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D002240:Carbohydrate Sequence; D005838:Genotype; D006003:Glycogen / Q000737:chemistry* / Q000235:genetics; D008112:Liver Glycogen / Q000737:chemistry*; D008433:Mathematics; D008954:Models, Biological; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D011817:Rabbits; D003313:Zea mays / Q000737:chemistry / Q000235:genetics*
chemical_list: D008112:Liver Glycogen; D009844:Oligosaccharides; D006003:Glycogen; D000687:Amylopectin