α-淀粉酶和淀粉葡萄糖苷酶在完全糊化状态下具有不同链长分布的淀粉消化过程中的相互作用,Food & Function

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α-淀粉酶和淀粉葡萄糖苷酶在完全糊化状态下具有不同链长分布的淀粉消化过程中的相互作用
Food & Function ( IF 5.1 ) Pub Date : 2022-02-19 , DOI: 10.1039/d1fo04256d
Xianglong Zhou ₁ , Chenrui Wang ₂ , Shuke Yue ₁ , Yong Zheng ₃ , Cheng Li ₄ , Wenwen Yu ₁

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淀粉葡萄糖苷酶（AMG）和α-淀粉酶（AMY）均参与人体小肠淀粉的消化，但它们与不同结构的淀粉分子的相互作用尚不清楚。在目前的研究中，使用具有不同直链淀粉含量（从蜡状到高直链淀粉含量）的淀粉来研究在完全糊化状态下体外淀粉消化率中的淀粉-酶相互作用。通过尺寸排阻色谱（SEC）获得消化前后的淀粉链长度分布（CLD），体外获得了具有单一或组合的 AMY 和 AMG 的消化图。结果表明，消化程度一般为AMG > AMG + AMY > AMY，说明AMG与AMY之间存在拮抗作用。这些酶组合对具有不同结构的淀粉的偏好不同。例如，与单一酶相比，AMG + AMY 可以以更快的速度消化蜡质淀粉。通过拟合斜率图的对数以及并行和顺序动力学模型的组合，两种不同的淀粉可消化部分（慢速与慢速）快速）被鉴定，并且AMG和AMY在消化快速消化部分中通常具有拮抗作用。最后，CLD 结果表明，消化后形成了原始淀粉样品中不存在的 DP 7-2000 的一小部分淀粉。DP > 2000 的淀粉部分可以被 AMY 非常快速地消化，而 DP 7-2000 的淀粉部分只能被 AMY 不太有效地消化，并且添加 AMG 可以进一步降低这种活性。该研究为了解淀粉-酶的相互作用以及它们在分子水平上对淀粉消化率的影响提供了重要信息。

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Mutual interactions between α-amylase and amyloglucosidase in the digestion of starch with distinct chain-length distributions at a fully gelatinized state

Amyloglucosidase (AMG) and α-amylase (AMY) are both involved in starch digestion in human small intestine, whereas their mutual interactions with starch molecules of distinct structures are still unknown. In the current study, starches with different amylose contents (from waxy to high amylose content) were used to investigate the starch–enzyme interactions in the in vitro starch digestibility at a fully gelatinized state. The starch chain-length distributions (CLDs) before and after digestion were obtained by size-exclusion chromatography (SEC), and the in vitro digestograms with a single or combined AMY and AMG were obtained. The results showed that the digestion extent generally followed an order of AMG > AMG + AMY > AMY, suggesting that there was an antagonistic effect between AMG and AMY. Starches with distinct structures were preferred differently by these enzyme combinations. For example, waxy starch could be digested at a much faster rate by AMG + AMY than by a single enzyme. By fitting to the logarithm of slope plot and the combination of parallel and sequential kinetics models, two different starch digestible fractions (slowly vs. rapidly) were identified, and AMG and AMY typically had an antagonistic effect in digesting the rapidly digestible fraction. Finally, the CLD results suggested that a small starch portion with DP 7–2000, not present in the original starch samples, was formed after the digestion. The starch portion with DP > 2000 could be very rapidly digested by AMY, whereas the starch portion with DP 7–2000 could only be less effectively digested by AMY, and the addition of AMG could further reduce this activity. This study provides important information for understanding the starch–enzyme interactions as well as their effects on starch digestibility at a molecular level.

更新日期：2022-02-19

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