Valueva T A, Revina T A, Mosolov V V
Bakh Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia.
Biochemistry (Mosc). 1997 Dec;62(12):1367-74.
Three protein inhibitors of proteolytic enzymes with molecular weights 21, 22, and 23 kD were isolated from potato tubers (Solanum tuberosum L.) by ammonium sulfate precipitation followed by gel and ion-exchange chromatography. The 21- and 22-kD proteins were shown to be serine proteinase inhibitors with different specificities. The 21-kD protein inhibits human leucocyte elastase and trypsin effectively, but it is less effective towards chymotrypsin. The 22-kD protein is an inhibitor of cysteine proteinases and suppresses the activities of papain, ficin, and bromelain with the same affinities. None of the isolated proteins inhibit subtilisin, pepsin, or cathepsin D. The 21-kD protein consists of two disulfide-linked polypeptide chains with molecular weights of 16.5 +/- 1 kD and 4.5 +/- 1 kD. The 22-kD and 23-kD proteins have a single polypeptide chain. The N-terminal 22-25 amino acid sequences of these three proteins were determined. These sequences have significant homology to other plant inhibitors from the Kunitz soybean inhibitor superfamily.
通过硫酸铵沉淀，随后进行凝胶和离子交换色谱法，从马铃薯块茎（茄属马铃薯）中分离出三种分子量分别为21、22和23 kD的蛋白水解酶蛋白抑制剂。结果表明，21 kD和22 kD的蛋白是具有不同特异性的丝氨酸蛋白酶抑制剂。21 kD的蛋白能有效抑制人白细胞弹性蛋白酶和胰蛋白酶，但对胰凝乳蛋白酶的抑制效果较差。22 kD的蛋白是半胱氨酸蛋白酶的抑制剂，对木瓜蛋白酶、无花果蛋白酶和菠萝蛋白酶具有相同亲和力的抑制活性。分离出的蛋白均不抑制枯草杆菌蛋白酶、胃蛋白酶或组织蛋白酶D。21 kD的蛋白由两条通过二硫键连接的多肽链组成，分子量分别为16.5±1 kD和4.5±1 kD。22 kD和23 kD的蛋白具有一条多肽链。测定了这三种蛋白的N端22 - 25个氨基酸序列。这些序列与来自Kunitz大豆抑制剂超家族的其他植物抑制剂具有显著的同源性。
