Department of Biological Sciences, State University of New York at Binghamton, Binghamton, New York 13902-6000.
Plant Physiol. 1991 Aug;96(4):1086-92. doi: 10.1104/pp.96.4.1086.
Protease K1 activity initiates the degradation of the Kunitz soybean trypsin inhibitor (KSTI) during germination and early seedling growth. This enzyme was purified nearly 1300-fold from the cotyledons of 4-day-old soybean (Glycine max [L.] Merrill) seedlings. Protease K1 is a cysteine protease with a molecular weight of approximately 29,000. It cleaves the native form of KSTI, Ti(a), to Ti(a) (m), the same modified form observed in vivo. In addition to attacking KSTI, protease K1 is also active toward the major Bowman-Birk soybean trypsin inhibitor, as well as the alpha, alpha', and beta subunits of soybean beta-conglycinin. The properties and temporal variation of protease K1 during germination indicate that it is responsible for initiating the degradation of both KSTI and Bowman-Birk soybean trypsin inhibitor in the soybean cotyledon.
蛋白酶 K1 活性在发芽和幼苗早期生长过程中启动 Kunitz 大豆胰蛋白酶抑制剂（KSTI）的降解。这种酶是从 4 天大的大豆（Glycine max [L.] Merrill）幼苗子叶中近 1300 倍纯化而来的。蛋白酶 K1 是一种半胱氨酸蛋白酶，分子量约为 29000。它将天然形式的 KSTI，Ti(a)，切割成 Ti(a)(m)，这是在体内观察到的相同修饰形式。除了攻击 KSTI 之外，蛋白酶 K1 还对主要的 Bowman-Birk 大豆胰蛋白酶抑制剂以及大豆β-伴大豆球蛋白的α、α'和β亚基具有活性。在发芽过程中蛋白酶 K1 的特性和时间变化表明，它负责启动大豆子叶中 KSTI 和 Bowman-Birk 大豆胰蛋白酶抑制剂的降解。
