United States Department of Agriculture - Agricultural Research Service, University of Missouri-Columbia , 205 Curtis Hall, Columbia, Missouri 65211, United States.
J Agric Food Chem. 2015 Feb 11;63(5):1352-9. doi: 10.1021/jf505220p. Epub 2015 Jan 29.
Soybean seed contains antinutritional compounds that inactivate digestive proteases, principally corresponding to two families: Kunitz trypsin inhibitors (KTi) and Bowman-Birk inhibitors (BBI). High levels of raw soybean/soybean meal in feed mixtures can cause poor weight gain and pancreatic abnormalities via inactivation of trypsin/chymotrypsin enzymes. Soybean protein meal is routinely heat-treated to inactivate inhibitors, a practice that is energy-intensive and costly and can degrade certain essential amino acids. In this work, we screened seed from 520 soybean accessions, using a combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblots with anti-Kunitz trypsin inhibitor antibodies. A soybean germplasm accession was identified with a mutation affecting an isoform annotated as nonfunctional (KTi1), which was determined to be synergistic with a previously identified mutation (KTi3-). We observed significant proteome rebalancing in all KTi mutant lines, resulting in dramatically increased BBI protein levels.
大豆种子含有抗营养化合物，会使消化蛋白酶失活，主要包括两类：Kunitz 胰蛋白酶抑制剂（KTi）和 Bowman-Birk 抑制剂（BBI）。在饲料混合物中添加大量生大豆/大豆粉可能会导致胰蛋白酶/糜蛋白酶失活，从而出现体重增长不良和胰腺异常。大豆蛋白饲料通常经过热处理以灭活抑制剂，但这种做法能耗大且成本高，还会导致某些必需氨基酸降解。在这项工作中，我们使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和抗 Kunitz 胰蛋白酶抑制剂抗体的免疫印迹法，对 520 份大豆种质资源进行了筛选。发现一个大豆种质资源的突变影响了一种被注释为无功能的同工型（KTi1），该突变与先前鉴定的突变（KTi3-）具有协同作用。我们观察到所有 KTi 突变株系的蛋白质组显著重新平衡，导致 BBI 蛋白水平显著增加。
