Novel Enzymic Degradation of Insoluble Polysaccharide-Analysis of Product Fixation and Its Application-

对不溶性多糖，特别是淀粉颗粒酶解过程中出现的新现象进行了分析，得到以下基本结果。(1)根据淀粉颗粒对葡萄糖淀粉酶消化的敏感性，将不同来源的淀粉颗粒分为三类，在反应的初始阶段，淀粉颗粒中所产生的葡萄糖占总葡萄糖的10-40%，这就是所谓的“产物固定”。“至于α-淀粉酶，大约10%的产品在颗粒中。在异淀粉酶催化消化中观察到最多的产物固定，内部产生30-60%的产物。(2)将马铃薯淀粉、shoti淀粉、amylomaize-7淀粉在其糊化温度下加热制备糊化淀粉，糊化淀粉对淀粉酶的水解敏感性比天然淀粉高2 ~ 15倍，而与颗粒结合的产物比例没有变化。(3)研究了异淀粉酶对糊化淀粉水解产物的固定作用。向反应混合物中加入乙醇以改变疏水性。随着乙醇浓度的增加，颗粒中的产物量增加。80%的乙醇浓度使产物完全固定。研究了反应温度对产物固定的影响，结果表明，低温下糊化淀粉中产物较多，长链的产物具有较高的固定度，在糊化温度下加热使淀粉颗粒结构发生轻微变化，增加了对淀粉酶消化的敏感性，保持了产物的固定性，3）在低温和高疏水性条件下，产物的量增加，氢键被认为主要有助于产物的固定。

Analysis on the novel phenomenon in the enzymatic degradation of insoluble polysaccharide, especially of starch granule, was done to obtain the fundamental results as follows.(1) Starch granules from various botanical sources were classified into three types of groups by the susceptibility to digestion of glucoamylase.In the initial stage of reaction, 10-40% of total glucose produced was found in the granule, which was termed "product fixation." As for alpha-amylasc, about 10% of product was in the granule. The most product fixation was observed in the isoamylase-catalyzed digestion, giving 30-60% product inside.(2) The starches most resistant against glucoamylase digestion, potato, shoti, amylomaize-7, were heated at their gelatinization temperatures to prepare the gelatinized starches.The gelatinized starches showed the 2-to 15-fold higher susceptibility to amylases hydrolysis than native ones with no change in the ratio of product which bound to granules.(3) The product fixation of isoamylase-catalyzed hydrolysis on the gelatinized starches was investigated. To the reaction mixture, ethanol was added to change the hydrophobicity. The amount of product in granule increased with the increase in the concentration of ethanol. Ethanol concentration of 80% gave the complete fixation of product. The effects of reaction temperature on the product fixation were examined, elucidating that at low temperature more product was in the gelatinized starches.The findings shows 1) that the product of long chain gave the high degree of product fixation, 2) that the mild structural change of starch granule given by heating in gelatinization temperature increased the susceptibility to amylases digestion and retained the fixation of product, and 3) that hydrogen bond was considered to contribute the product fixation mainly since the amount of product increased at low temperature and in the highly hydrophobic condition.