Sun Z T, Henson C A
Department of Agronomy, University of Wisconsin, Madison 53706.
Arch Biochem Biophys. 1991 Feb 1;284(2):298-305. doi: 10.1016/0003-9861(91)90299-x.
Extracts of germinated barley (Hordeum vulgare L.) seeds of 41 different genotypes were analyzed for their activities of alpha-amylase, beta-amylase, alpha-glucosidase, and debranching enzyme and for their abilities to hydrolyze boiled soluble starch, nonboiled soluble starch, and starch granules extracted from barley seeds with water. Linear correlation analysis, used to quantitate the interactions between the seven parameters, revealed that boiled soluble starch was not a good substrate for predicting activities of enzymes functioning in in vivo starch hydrolysis as the extracts' abilities to hydrolyze boiled soluble starch was not correlated with their abilities to hydrolyze native starch granules. Activities of alpha-amylase and alpha-glucosidase were positively and significantly correlated with the seed extracts' abilities to hydrolyze all three starches. beta-Amylase was only significantly correlated with hydrolysis of boiled soluble starch. No significant correlations existed between debranching enzyme activity and hydrolysis of any of the three starches. Interactions between the four enzymes as they functioned together to hydrolyze the three types of starch were evaluated by path coefficient analysis. alpha-Amylase contributed to hydrolyses of all three starches primarily by its direct effect (noninteractive component). This direct contribution increased as the substrate progressed from the completely artificial boiled soluble starch, to the most physiologically significant substrate, native starch granules. alpha-Glucosidase contributed to the hydrolysis of boiled soluble starch primarily by its direct effect (noninteractive) yet contributed to starch granule hydrolysis primarily via its interaction with alpha-amylase (indirect effect). The contribution of beta-amylase to hydrolysis of boiled soluble starch was direct and it did not contribute significantly to hydrolysis of native starch granules.
对41种不同基因型的发芽大麦（Hordeum vulgare L.）种子提取物进行了α-淀粉酶、β-淀粉酶、α-葡萄糖苷酶和脱支酶活性分析，以及它们水解煮沸的可溶性淀粉、未煮沸的可溶性淀粉和用水从大麦种子中提取的淀粉颗粒的能力分析。用于定量七个参数之间相互作用的线性相关分析表明，煮沸的可溶性淀粉不是预测体内淀粉水解中起作用的酶活性的良好底物，因为提取物水解煮沸的可溶性淀粉的能力与其水解天然淀粉颗粒的能力不相关。α-淀粉酶和α-葡萄糖苷酶的活性与种子提取物水解所有三种淀粉的能力呈正相关且显著相关。β-淀粉酶仅与煮沸的可溶性淀粉的水解显著相关。脱支酶活性与三种淀粉中任何一种的水解之间均无显著相关性。通过通径系数分析评估了四种酶共同作用水解三种淀粉时的相互作用。α-淀粉酶主要通过其直接作用（非交互成分）促进所有三种淀粉的水解。随着底物从完全人工的煮沸可溶性淀粉发展到最具生理意义的底物天然淀粉颗粒，这种直接贡献增加。α-葡萄糖苷酶主要通过其直接作用（非交互）促进煮沸的可溶性淀粉的水解，但主要通过与α-淀粉酶的相互作用（间接作用）促进淀粉颗粒的水解。β-淀粉酶对煮沸的可溶性淀粉水解的贡献是直接的，对天然淀粉颗粒的水解没有显著贡献。
