Rosenthal P J, Kim K, McKerrow J H, Leech J H
J Exp Med. 1987 Sep 1;166(3):816-21. doi: 10.1084/jem.166.3.816.
We have identified and characterized three stage-specific proteinases of Plasmodium falciparum that are active at neutral pH. We analyzed ring-, trophozoite-, schizont-, and merozoite-stage parasites by gelatin substrate PAGE and characterized the identified proteinases with class-specific proteinase inhibitors. No proteinase activity was detected with rings. Trophozoites had a 28 kD proteinase that was inhibited by inhibitors of cysteine proteinases. Mature schizonts had a 35-40 kD proteinase that also was inhibited by cysteine proteinase inhibitors. Merozoite fractions had a 75 kD proteinase that was inhibited by serine proteinase inhibitors. The stage-specific activity of these proteinases and the correlation between the effects of proteinase inhibitors on the isolated enzymes with the effects of the inhibitors on whole parasites suggest potential critical functions for these proteinases in the life cycle of malaria parasites.
我们已经鉴定并表征了恶性疟原虫的三种在中性pH值下具有活性的阶段特异性蛋白酶。我们通过明胶底物聚丙烯酰胺凝胶电泳分析了环状体、滋养体、裂殖体和裂殖子阶段的寄生虫，并用类特异性蛋白酶抑制剂对鉴定出的蛋白酶进行了表征。环状体未检测到蛋白酶活性。滋养体有一个28 kD的蛋白酶，被半胱氨酸蛋白酶抑制剂抑制。成熟裂殖体有一个35 - 40 kD的蛋白酶，也被半胱氨酸蛋白酶抑制剂抑制。裂殖子组分有一个75 kD的蛋白酶，被丝氨酸蛋白酶抑制剂抑制。这些蛋白酶的阶段特异性活性以及蛋白酶抑制剂对分离酶的作用与对整个寄生虫的作用之间的相关性表明，这些蛋白酶在疟原虫的生命周期中可能具有关键功能。
