Valdes-Rodriguez S, Segura-Nieto M, Chagolla-Lopez A, Verver y Vargas-Cortina A, Martinez-Gallardo N, Blanco-Labra A
Department of Biotechnology and Biochemistry, Centro de Investigacion y de Estudios Avanzados, Instituto Politécnico Nacional, Unidad Irapuato, Guanajuato, Mexico.
Plant Physiol. 1993 Dec;103(4):1407-12. doi: 10.1104/pp.103.4.1407.
A protein proteinase inhibitor was purified from a seed extract of amaranth (Amaranthus hypochondriacus) by precipitation with (NH4)2SO4, gel-filtration chromatography, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography. It is a 69-amino acid protein with a high content of valine, arginine, and glutamic acid, but lacking in methionine. The inhibitor has a relative molecular weight of 7400 and an isoelectric point of 7.5. It is a serine proteinase inhibitor that recognizes chymotrypsin, trypsin, and trypsin-like proteinase activities extracted from larvae of the insect Prostephanus truncatus. This inhibitor belongs to the potato-I inhibitor family, showing the closest homology (59.5%) with the Lycopersicum peruvianum trypsin inhibitor, and (51%) with the proteinase inhibitor 5 extracted from the seeds of Cucurbita maxima. The position of the lysine-aspartic acid residues present in the active site of the amaranth inhibitor are found in almost the same relative position as in the inhibitor from C. maxima.
通过硫酸铵沉淀、凝胶过滤色谱、离子交换色谱和反相高效液相色谱从苋属植物（皱果苋）种子提取物中纯化出一种蛋白质蛋白酶抑制剂。它是一种由69个氨基酸组成的蛋白质，缬氨酸、精氨酸和谷氨酸含量高，但缺乏甲硫氨酸。该抑制剂的相对分子量为7400，等电点为7.5。它是一种丝氨酸蛋白酶抑制剂，可识别从咖啡豆象幼虫中提取的胰凝乳蛋白酶、胰蛋白酶和类胰蛋白酶活性。这种抑制剂属于马铃薯-I抑制剂家族，与秘鲁番茄胰蛋白酶抑制剂的同源性最高（59.5%），与从南瓜种子中提取的蛋白酶抑制剂5的同源性为（51%）。苋属植物抑制剂活性位点中赖氨酸-天冬氨酸残基的位置与南瓜属抑制剂中的位置几乎处于相同的相对位置。
