Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Department of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
Carbohydr Polym. 2020 Nov 1;247:116674. doi: 10.1016/j.carbpol.2020.116674. Epub 2020 Jun 30.
Starch granule-associated proteins (SGAPs) include granule-surface proteins (SGSPs) and granule-channel proteins (SGCPs). To investigate impacts of SGAPs on amyloglucosidase (AMG) hydrolysis, waxy and non-waxy rice starches had their SGCPs or SGAPs removed. Removal of SGAPs or SGCPs did not affect morphology and amylopectin chain distribution but decreased relative crystallinity. Removal of SGAPs increased the digestion rate, AMG binding ability and pore diameter of hydrolyzed granules, and accelerated changes in relative crystallinity and destruction of crystalline region on hydrolysis. However, after removing SGCPs, AMG only bound to surface and attacked of the fingerprint of protein bodies on granules, with decreased hydrolysis rate. The degree of change in hydrolysis rate was not determined by SGCPs content of rice starch. These results implied that SGCPs had a more dominant role in AMG hydrolysis of rice starch than did SGSPs. This study provides novel information about the role of SGAPs in AMG hydrolysis mechanisms.
淀粉粒相关蛋白（SGAPs）包括颗粒表面蛋白（SGSPs）和颗粒通道蛋白（SGCPs）。为了研究 SGAPs 对糖化酶（AMG）水解的影响，对蜡质和非蜡质大米淀粉进行了 SGCPs 或 SGAPs 的去除。去除 SGAPs 或 SGCPs 并不影响形态和支链淀粉链分布，但降低了相对结晶度。去除 SGAPs 增加了水解颗粒的消化率、AMG 结合能力和孔径，并加速了相对结晶度的变化和结晶区在水解过程中的破坏。然而，去除 SGCPs 后，AMG 仅结合到颗粒表面和蛋白质体指纹的表面，并降低了水解速率。水解速率的变化程度不受大米淀粉中 SGCPs 含量的影响。这些结果表明，SGCPs 在 AMG 水解大米淀粉中的作用比 SGSPs 更为重要。本研究为 SGAPs 在 AMG 水解机制中的作用提供了新的信息。
