Molecular structures of amyloses of various plants

研究了玉米、水稻、小麦、板栗、苦豆、百合、永麻、木薯和甘薯中直链淀粉的结构。谷物直链淀粉通过涉及超离心的程序纯化，并且避免了传统的高压灭菌程序，因为它降解了直链淀粉。水稻（3个籼稻品种和2个粳稻品种）和甘薯（Koganesengan、miniyutaka和Norin-2品种）的直链淀粉结构几乎没有品种差异。籽粒直链淀粉的平均聚合度为960 ~ 3280，籽粒直链淀粉分子量较小。大多数直链淀粉每分子包含3-5个链，但木薯和甘薯的直链淀粉有8-10个链。通过对直链淀粉-极限糊精的结构分析，阐明了直链淀粉支链分子的结构。小麦、长毛、百合、红薯和木薯淀粉的直链淀粉含有较大的支链分子，而玉米和栗子的直链淀粉则含有较小的支链分子。玉米、苦荞麦、长叶苗和百合的支链分子具有较长的内链（dp, 150），而栗子和小麦的支链分子具有较短的内链（dp, 60-91）。玉米的支链分子至少包含5条链，而小麦、木薯和甘薯的支链则有14-17条。其余的来自8-11链。水稻、小麦、栗子和长毛直链淀粉支链分子的摩尔分数较低（-1/3），而甘薯直链淀粉支链分子的摩尔分数较高（-2/3）。其余的由几乎相等数量的线状和支状分子组成。这些结果表明，不同来源的直链淀粉具有各自的特征结构。

The structures of amyloses from corn, rice, wheat, chestnut, kuzu, lily, nagaimo, tapioca and sweet potato were investigated in detail. The cereal amyloses were purified by the procedures involving ultracentrifugation, and the conventional autoclaving procedure was avoided, since it degraded the amyloses. There was almost no variety difference in the structures of amyloses each from rices (3 indica and 2 japonica varieties) and sweet potatoes (Koganesengan, Minamiyutaka and Norin-2 varieties). The molecular sizes of the amyloses ranged from the average degree of polymerization (d.p.) of 960 to 3280, and the cereal amyloses were smaller than the others. Most amyloses comprised 3-5 chains per molecule, but the tapioca and sweet potato amyloses had 8-10 chains. The structures of branched molecules of the amyloses were elucidated by the structural analyses of beta-limit dextrins of the amyloses. The wheat, nagaimo, lily, sweet potato and tapioca amyloses contained large branched-molecules, while the corn and chestnut amyloses had small ones. The corn, kuzu, nagaimo and lily branched-molecules had long inner chains (d.p., 150), while the chestnut and wheat amyloses had short ones (d.p., 60-91). The corn branched-molecules comprised the least 5 chains, while the wheat, tapioca and sweet potato had from 14-17 chains. The remainder had from 8-11 chains. The rice, wheat, chestnut and nagaimo amyloses contained low molar fractions (-1/3) of the branched molecules, while the sweet potato amylose had high molar fraction (-2/3). The remainder comprised nearly equal numbers of linear and branched molecules. These results indicate that the amyloses of various origins have their own characteristic structures.